A013706 Decimal expansion of 2*Sum_{k=1..50000} (-1)^(k-1)/(2k-1).
1, 5, 7, 0, 7, 8, 6, 3, 2, 6, 7, 9, 4, 8, 9, 7, 6, 1, 9, 2, 3, 1, 3, 2, 1, 1, 9, 1, 6, 3, 9, 7, 5, 2, 0, 5, 2, 0, 9, 8, 5, 8, 3, 3, 1, 4, 6, 8, 7, 5, 5, 7, 9, 6, 2, 5, 8, 7, 4, 4, 5, 2, 6, 8, 5, 0, 4, 1, 0, 7, 5, 6, 4, 1, 2, 2, 1, 6, 5, 3, 4, 8, 1, 2, 3, 5, 6, 6, 2, 0, 9, 0, 5, 5, 0, 9, 7, 3, 5, 2, 6, 8, 8, 4, 3, 6, 3, 2, 7, 4, 2, 5, 0, 9, 3, 7, 0, 4, 8, 2, 5, 0, 6, 1, 9, 3
Offset: 1
Examples
Pi/2: 1.570796326794896619231321691639751442098584699687552910487472... This sum: 1.570786326794897619231321191639752052098583314687557962587445... ..........================^=================^^^======^^^^=====^=^^^===^^...
Links
- J. M. Borwein, P. B. Borwein and K. Dilcher, Pi, Euler numbers and asymptotic expansions, Amer. Math. Monthly, 96 (1989), 681-687.
- J. M. Borwein, P. B. Borwein and K. Dilcher, Pi, Euler numbers and asymptotic expansions, Amer. Math. Monthly, 96 (1989), 681-687.
- J. M. Borwein and R. M. Corless, Review of "An Encyclopedia of Integer Sequences" by N. J. A. Sloane and Simon Plouffe, SIAM Review, 38 (1996), 333-337.
Crossrefs
Programs
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Mathematica
RealDigits[2*Sum[(-1)^(k-1)/(2k-1),{k,50000}],10,130][[1]] (* Harvey P. Dale, Oct 23 2012 *)
Extensions
Entry revised by N. J. A. Sloane, Sep 08 2012
Comments