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A216548 Decimal expansion of 4*Sum_{k=1..5000000} (-1)^(k-1)/(2k-1). 10
3, 1, 4, 1, 5, 9, 2, 4, 5, 3, 5, 8, 9, 7, 9, 3, 2, 3, 8, 4, 6, 4, 6, 4, 3, 3, 8, 3, 2, 7, 9, 5, 0, 2, 7, 8, 4, 1, 9, 7, 1, 6, 9, 3, 9, 9, 3, 8, 7, 3, 0, 5, 8, 2, 0, 9, 7, 4, 9, 4, 1, 8, 2, 2, 3, 0, 7, 8, 1, 6, 4, 0, 7, 2, 9, 6, 6, 2, 8, 9, 9, 8, 6, 2, 7, 4, 9, 4, 2, 7, 2, 3, 4, 2, 1, 1, 7, 4, 6, 6, 7, 0, 4, 1, 1, 0, 0, 8, 6, 1, 2, 5, 4, 5, 2, 0, 6, 3, 7, 4, 7, 5, 7, 4, 8 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

An approximation to Pi.

REFERENCES

J. M. Borwein, P. B. Borwein and K. Dilcher, Pi, Euler numbers and asymptotic expansions, Amer. Math. Monthly, 96 (1989), 681-687.

LINKS

Table of n, a(n) for n=1..125.

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.

EXAMPLE

3.1415924535897932384646433832795027841971693993873058209749418223...

CROSSREFS

Cf. A000796, A216542, A013706, A216543, A216544, A216545, A013705, A216546, A216547, A216548.

Cf. also A195793.

Sequence in context: A216543 A152040 A013705 * A087478 A112602 A000796

Adjacent sequences:  A216545 A216546 A216547 * A216549 A216550 A216551

KEYWORD

cons,nonn

AUTHOR

N. J. A. Sloane, Sep 08 2012

STATUS

approved

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Last modified May 22 08:33 EDT 2013. Contains 225513 sequences.