A069984 1123+21460n.

1123, 22583, 44043, 65503, 86963, 108423, 129883, 151343, 172803, 194263, 215723, 237183, 258643, 280103, 301563, 323023, 344483, 365943, 387403, 408863, 430323, 451783, 473243, 494703, 516163, 537623, 559083, 580543, 602003, 623463

Offset

0,1

Comments

Arises in an important Ramanujan formula for Pi: 4/Pi=1123/882-22583/882^3*(1/2*(1*3)/4^2)+...

References

L. Berggren, J. Borwein and P. Borwein, "Pi: A source book", Springer, second edition, p. 328.

S. Ramanujan, "Modular equations and approximations to Pi", Quart. J. Pure Appl. Math., v. 45, 1914, p. 350-372.

Links

Harvey P. Dale, Table of n, a(n) for n = 0..1000

Tanya Khovanova, Recursive Sequences

Index entries for linear recurrences with constant coefficients, signature (2,-1).

Formula

a(0)=1123, a(1)=22583, a(n)=2*a(n-1)-a(n-2). - Harvey P. Dale, Feb 04 2015

Mathematica

21460*Range[0, 30]+1123 (* or *) LinearRecurrence[{2, -1}, {1123, 22583}, 30] (* Harvey P. Dale, Feb 04 2015 *)

Crossrefs

Sequence in context: A200072 A261264 A125840 * A358420 A104285 A260898

Adjacent sequences: A069981 A069982 A069983 * A069985 A069986 A069987

Keyword

easy,nonn

Author

Benoit Cloitre, May 01 2002

Status

approved