A308717 Decimal expansion of cosh(sqrt(3)*Pi/2)*sech(Pi/2).
3, 0, 4, 0, 1, 9, 1, 5, 5, 1, 6, 4, 2, 5, 5, 3, 0, 7, 5, 6, 0, 1, 8, 6, 0, 0, 2, 7, 9, 0, 0, 7, 5, 7, 2, 3, 3, 8, 2, 3, 8, 5, 4, 9, 0, 5, 8, 7, 9, 1, 7, 1, 6, 7, 7, 9, 4, 1, 6, 5, 9, 7, 5, 1, 8, 4, 0, 8, 8, 5, 3, 9, 2, 5, 2, 3, 3, 2, 0, 4, 4, 1, 9, 6, 5, 1, 4, 6, 1, 8, 2, 9, 9, 0, 2, 5, 5, 0, 2, 1, 9, 7, 1, 1, 2, 0, 4, 8, 3, 0, 3, 9, 2, 2, 3, 1, 0, 5, 0, 6
Offset: 1
Examples
3.040191551642553075601860027900757233823854905879...
Links
- Kelvin Voskuijl, Table of n, a(n) for n = 1..20000
Programs
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Mathematica
RealDigits[Cosh[Sqrt[3] Pi/2] Sech[Pi/2], 10, 120][[1]]
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PARI
cosh(sqrt(3)*Pi/2)/cosh(Pi/2) \\ Michel Marcus, Jun 20 2019
Formula
Equals Product_{k>=0} (1 + 1/(2*k*(k + 1) + 1)).
Equals Product_{k>=0} (1 + 1/A001844(k)).