A372775 Decimal expansion of Sum_{k>=0} (2*k + 1)!/(3*k)!.

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

Offset

1,1

Links

Table of n, a(n) for n=1..86.

Formula

Equals hypergeometric([1, 3/2], [1/3, 2/3], 4/27).

Example

2.181344655134598339389148456673991324665...

Mathematica

s = Sum[ (2 k + 1)!/(3 k)!, {k, 0, Infinity}]
d = N[s, 100]
First[RealDigits[d]]
N[HypergeometricPFQ[{1, 3/2}, {1/3, 2/3}, 4/27], 100]

Prog

(PARI) suminf(k=0, (2*k + 1)!/(3*k)!) \\ Michel Marcus, Jun 01 2024

Crossrefs

Cf. A372776.

Sequence in context: A341406 A342937 A353571 * A254027 A284346 A318651

Adjacent sequences: A372772 A372773 A372774 * A372776 A372777 A372778

Keyword

nonn,cons

Author

Clark Kimberling, May 31 2024

Status

approved