

A001113


Decimal expansion of e.
(Formerly M1727 N0684)


322



2, 7, 1, 8, 2, 8, 1, 8, 2, 8, 4, 5, 9, 0, 4, 5, 2, 3, 5, 3, 6, 0, 2, 8, 7, 4, 7, 1, 3, 5, 2, 6, 6, 2, 4, 9, 7, 7, 5, 7, 2, 4, 7, 0, 9, 3, 6, 9, 9, 9, 5, 9, 5, 7, 4, 9, 6, 6, 9, 6, 7, 6, 2, 7, 7, 2, 4, 0, 7, 6, 6, 3, 0, 3, 5, 3, 5, 4, 7, 5, 9, 4, 5, 7, 1, 3, 8, 2, 1, 7, 8, 5, 2, 5, 1, 6, 6, 4, 2, 7, 4, 2, 7, 4, 6
(list;
constant;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


COMMENTS

e is sometimes called Euler's constant, also Napier's constant.
Also, decimal expansion of sinh(1)+cosh(1).  Mohammad K. Azarian, Aug 15 2006
If m and n are any integers with n > 1, then e  m/n > 1/(S(n)+1)!, where S(n) = A002034(n) is the smallest number such that n divides S(n)!.  Jonathan Sondow, Sep 04 2006
Abs(A000166*eA000142) > 0.  Seiichi Kirikami, Oct 12 2011
Euler's constant (also known as EulerMascheroni constant) is gamma=0.57721... and Euler's number is e=2.71828...  Mohammad K. Azarian, Dec 29 2011
One of the many continued fraction expressions for e is 2 + 2/3+ 3/3+ 4/4+ 5/5+ 6/6+ … from Ramanujan (18871920).  Robert G. Wilson v, Jul 16 2012


REFERENCES

Mohammad K. Azarian, An Expansion of e, Problem # B765, Fibonacci Quarterly, Vol. 32, No. 2, May 1994, p. 181. Solution appeared in Vol. 33, No. 4, Aug. 1995, p. 377.
Mohammad K. Azarian, Euler's Number Via Difference Equations, International Journal of Contemporary Mathematical Sciences, Vol. 7, 2012, No. 22, pp. 1095  1102.
S. R. Finch, Mathematical Constants, Cambridge, 2003, Section 1.3.
E. Maor, e: The Story of a Number, Princeton Univ. Press, 1994.
Clifford A. Pickover, A Passion for Mathematics, Wiley, 2005; see p. 52.
G. W. Reitwiesner, An ENIAC determination of pi and e to more than 2000 decimal places. Math. Tables and Other Aids to Computation 4, (1950). 1115.
D. Shanks and J. W. Wrench, Jr., Calculation of e to 100,000 decimals, Math. Comp., 23 (1969), 679680.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
J. Sondow, A geometric proof that e is irrational and a new measure of its irrationality, Amer. Math. Monthly 113 (2006) 637641 (article), 114 (2007) 659 (addendum).


LINKS

N. J. A. Sloane, Table of 50000 digits of e labeled from 1 to 50000 [based on the ICON Project link below]
Dave's Math Tables, e
X. Gourdon, Plouffe's Inverter, e to 1.250 billion digits
X. Gourdon and P. Sebah, The constant e and its computation
ICON Project, e to 50000 places
R. Nemiroff and J. Bonnell, The first 5 million digits of the number e
Remco Niemeijer, , Digits Of E, programmingpraxis
J. J. O'Connor & E. F. Robertson, The number e
Simon Plouffe, A million digits
E. Sandifer, How Euler Did It, Who proved e is irrational?
JeanLouis Sigrist, Le premier million de decimales de e. [From Lekraj Beedassy, Sep 28 2009]
J. Sondow, A geometric proof that e is irrational and a new measure of its irrationality
J. Sondow and K. Schalm, Which partial sums of the Taylor series for e are convergents to e? (and a link to the primes 2, 5, 13, 37, 463), II, Gems in Experimental Mathematics (T. Amdeberhan, L. A. Medina, and V. H. Moll, eds.), Contemporary Mathematics, vol. 517, Amer. Math. Soc., Providence, RI, 2010.
G. Villemin's Almanach of Numbers, Constant"e"
Eric Weisstein's World of Mathematics, e
Eric Weisstein's World of Mathematics, e Digits
Eric Weisstein's World of Mathematics, Factorial Sums
Eric Weisstein's World of Mathematics, Uniform Sum Distribution
Wikipedia, E (mathematical constant)


FORMULA

e = Sum_{k >= 0} 1/k! = lim_{x > 0} (1+x)^(1/x).
e is the unique positive root of the equation Integral_{u = 1..x} du/u = 1.
exp(1) = (16/31*(sum((1/2)^n*(1/2*n^3+1/2*n+1)/n!,n=1..infinity) +1))^2. Robert Israel confirmed that above formula is correct, saying: "In fact, sum(n^j*t^n/n!, n=0..infinity) = P_j(t)*exp(t) where P_0(t) = 1 and for j >= 1, P_j(t) = t (P_(j1)'(t) + P_(j1)(t)). Your sum is 1/2*P_3(1/2) + 1/2*P_1(1/2) + P_0(1/2)."  Alexander R. Povolotsky, Jan 04 2009
exp(1) = (1+ sum((1+n+n^3)/n!, n=1..infinity))/7.  Alexander R. Povolotsky, Sep 14 2011


EXAMPLE

2.71828182845904523536028747135266249775724709369995957496696762772407663\
0353547594571382178525166427427466391932003059921817413596629043572900334\
295260595630738132328627943490763233829880753195251019...


MAPLE

Digits := 200: it := evalf((exp(1))/10, 200): for i from 1 to 200 do printf(`%d, `, floor(10*it)): it := 10*itfloor(10*it): od:


MATHEMATICA

RealDigits[E, 10, 120][[1]] (* Harvey P. Dale, Nov 14 2011 *)


PROG

(PARI) { default(realprecision, 50080); x=exp(1); for (n=1, 50000, d=floor(x); x=(xd)*10; write("b001113.txt", n, " ", d)); } \\ Harry J. Smith, Apr 15 2009
(Haskell) See Niemeijer link.
a001113 n = a001113_list !! (n1)
a001113_list = eStream (1, 0, 1)
[(n, a * d, d)  (n, d, a) < map (\k > (1, k, 1)) [1..]] where
eStream z xs'@(x:xs)
 lb /= approx z 2 = eStream (mult z x) xs
 otherwise = lb : eStream (mult (10, 10 * lb, 1) z) xs'
where lb = approx z 1
approx (a, b, c) n = div (a * n + b) c
mult (a, b, c) (d, e, f) = (a * d, a * e + b * f, c * f)
 Reinhard Zumkeller, Jun 12 2013


CROSSREFS

Cf. A002034, A122214, A122215, A122216, A122217, A122416, A122417.
Expansion of e in base b: A004593 (b=2), A004594 (b=3), A004595 (b=4), A004596 (b=5), A004597 (b=6), A004598 (b=7), A004599 (b=8), A004600 (b=9), this sequence (b=10), A170873 (b=16).  Jason Kimberley, Dec 05 2012
Sequence in context: A170936 A111714 A060302 * A248685 A182587 A248677
Adjacent sequences: A001110 A001111 A001112 * A001114 A001115 A001116


KEYWORD

nonn,cons,nice,core


AUTHOR

N. J. A. Sloane


EXTENSIONS

Maple code from James A. Sellers, Feb 13 2001


STATUS

approved



