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A232883 Decimal expansion of sum( i>=0, 1/(2*i^2+1) ). 3
1, 6, 3, 7, 1, 6, 0, 2, 6, 7, 1, 1, 7, 9, 6, 7, 2, 4, 6, 4, 3, 7, 2, 6, 4, 4, 9, 5, 8, 0, 0, 5, 7, 3, 5, 7, 3, 9, 3, 7, 2, 6, 3, 3, 6, 8, 4, 5, 0, 6, 9, 4, 6, 1, 9, 2, 6, 2, 2, 8, 2, 4, 1, 9, 9, 2, 6, 6, 6, 9, 0, 2, 9, 7, 0, 6, 0, 9, 1, 1, 2, 5, 8, 2, 4, 3, 3, 0 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Ivan Panchenko, Table of n, a(n) for n = 1..1000

FORMULA

Equals 1/2 + ( Pi/sqrt(2) ) /tanh( Pi/sqrt(2) ) /2.

EXAMPLE

1.6371602671179672464372644958005735739372633684506946192622824199...

MATHEMATICA

RealDigits[1/2 + Pi/Sqrt[2]/Tanh[Pi/Sqrt[2]]/2, 10, 90][[1]]

CROSSREFS

Cf. A072691: sum( i>=1, 1/(2*i^2) ); A113319: sum( i>=0, 1/(i^2+1) ).

Sequence in context: A024563 A265179 A215608 * A119643 A187747 A073223

Adjacent sequences:  A232880 A232881 A232882 * A232884 A232885 A232886

KEYWORD

nonn,cons

AUTHOR

Bruno Berselli, Dec 02 2013

STATUS

approved

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Last modified May 30 03:31 EDT 2017. Contains 287305 sequences.