

A001467


Denominators of an expansion for Pi.
(Formerly M4464 N1893)


2




OFFSET

0,4


REFERENCES

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).


LINKS

Table of n, a(n) for n=0..8.
Mohammad K. Azarian, An Expression for Pi, Problem #870, College Mathematics Journal, Vol. 39, No. 1, January 2008, p. 66. Solution appeared in Vol. 40, No. 1, January 2009, pp. 6264.
H. E. Salzer, The approximation of numbers as sums of reciprocals, Amer. Math. Monthly, 54 (1947), 135142.
J. W. Wrench, Jr., Letter to N. J. A. Sloane, Mar 27 1974
Index entries for sequences related to the number Pi


FORMULA

Numerators are 1.


EXAMPLE

a(4) = 791 since Pi  (1/1)  (1/1)  (1/1)  (1/7) = 0.001264489... is closer to 1/(791) = 0.001264222... than to 1/(790) = 0.0012658228...


PROG

(PARI) x=Pi; for(k=0, 8, if(x<1, d=round(1/x), d=1); x=x1/d; print(d, ", ")) \\ Jaume Oliver Lafont, Feb 21 2009


CROSSREFS

Cf. A001466, A014013, A073422.
Sequence in context: A182282 A171245 A014013 * A278438 A279120 A047788
Adjacent sequences: A001464 A001465 A001466 * A001468 A001469 A001470


KEYWORD

sign,frac


AUTHOR

N. J. A. Sloane


EXTENSIONS

Edited by Henry Bottomley, Jul 30 2002


STATUS

approved



