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A308715
Decimal expansion of cosh(Pi/2).
8
2, 5, 0, 9, 1, 7, 8, 4, 7, 8, 6, 5, 8, 0, 5, 6, 7, 8, 2, 0, 0, 9, 9, 9, 5, 6, 4, 3, 2, 6, 9, 4, 0, 5, 9, 4, 8, 2, 1, 2, 0, 2, 4, 3, 5, 8, 1, 4, 8, 1, 5, 2, 2, 7, 4, 0, 4, 7, 9, 7, 5, 6, 8, 6, 1, 4, 8, 9, 8, 5, 8, 9, 1, 0, 8, 8, 5, 3, 2, 1, 3, 8, 2, 6, 8, 6, 5, 2, 5, 2, 2, 2, 2, 4, 6, 5, 4, 6, 9, 4, 9, 9, 8, 9, 0, 1, 9, 9, 8, 0, 2, 1, 4, 6, 7, 0, 7, 5, 5, 3
OFFSET
1,1
FORMULA
Equals Product_{k>=1} (1 + 1/(2*k - 1)^2).
Equals Product_{k>=0} (1 + 1/A016754(k)).
EXAMPLE
2.50917847865805678200999564326940594821202435...
MATHEMATICA
RealDigits[Cosh[Pi/2], 10, 120][[1]]
PROG
(PARI) cosh(Pi/2) \\ Michel Marcus, Jun 20 2019
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Ilya Gutkovskiy, Jun 19 2019
STATUS
approved