A145428 Decimal expansion of Sum_{n>=1} 3^n*(n!)^2/(2n)!.

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, 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, 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

Offset

2,3

References

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

Links

Table of n, a(n) for n=2..94.

Formula

Equals 3 + 10 * A019694 * A020760.

Example

10.255197456936871...

Maple

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

Mathematica

RealDigits[4*Pi/Sqrt[3] + 3, 10, 120][[1]] (* Amiram Eldar, Aug 23 2024 *)

Crossrefs

Cf. A019694, A020760.

Sequence in context: A160177 A320428 A340422 * A086283 A153759 A269992

Adjacent sequences: A145425 A145426 A145427 * A145429 A145430 A145431

Keyword

cons,easy,nonn

Author

R. J. Mathar, Feb 08 2009

Status

approved