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Decimal expansion of Sum_{n>=1} 3^n*(n!)^2/(2n)!.
0

%I #7 Aug 23 2024 05:29:16

%S 1,0,2,5,5,1,9,7,4,5,6,9,3,6,8,7,1,4,0,2,3,7,6,3,1,3,0,3,0,5,6,8,6,2,

%T 2,9,2,9,1,3,6,2,6,4,9,9,2,3,7,0,9,6,2,3,0,2,2,7,9,5,3,9,7,4,1,5,5,2,

%U 4,9,2,7,2,4,5,0,5,4,1,5,5,3,4,7,3,6,4,9,9,9,5,2,8

%N Decimal expansion of Sum_{n>=1} 3^n*(n!)^2/(2n)!.

%D Alexander Apelblat, Tables of Integrals and Series, Harri Deutsch, 1996, 4.1.34.

%F Equals 3 + 10 * A019694 * A020760.

%e 10.255197456936871...

%p evalf(4*Pi/3^(1/2) + 3, 100);

%t RealDigits[4*Pi/Sqrt[3] + 3, 10, 120][[1]] (* _Amiram Eldar_, Aug 23 2024 *)

%Y Cf. A019694, A020760.

%K cons,easy,nonn

%O 2,3

%A _R. J. Mathar_, Feb 08 2009