login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A001467 Denominators of an expansion for Pi.
(Formerly M4464 N1893)
2
1, 1, 1, 7, -791, -3748629, 151648960887729, -1323497544567561138595307148089, 41444465282455711991644958522615049159671653083333293470875123 (list; graph; refs; listen; history; text; internal format)
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. 62-64.

H. E. Salzer, The approximation of numbers as sums of reciprocals, Amer. Math. Monthly, 54 (1947), 135-142.

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=x-1/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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 20 19:34 EDT 2018. Contains 316401 sequences. (Running on oeis4.)