A073595 Denominator of b(n) = Sum_{k=1..n} (-1)^(k+1)/k*Sum_{i=0..k-1} (-1)^i/(2*i+1).

1, 3, 45, 315, 1575, 51975, 4729725, 4729725, 18555075, 4583103525, 50414138775, 1159525191825, 793359341775, 15073827493725, 2185704986590125, 67756854584293875, 1151866527932995875, 3455599583798987625, 2429286507410688300375, 2429286507410688300375

Offset

1,2

Links

Amiram Eldar, Table of n, a(n) for n = 1..772

Formula

Limit_{n -> infinity} b(n) = G, the Catalan constant (A006752).

Mathematica

Denominator[Accumulate[Table[(-1)^(k + 1)/k * Sum[(-1)^i/(2*i + 1), {i, 0, k - 1}], {k, 1, 20}]]] (* Amiram Eldar, May 05 2022 *)

Prog

(PARI) a(n)=denominator(sum(k=1, n, (-1)^(k+1)/k*sum(i=0, k-1, (-1)^i/(2*i+1))))

Crossrefs

Cf. A006752, A073594 (numerators).

Sequence in context: A062346 A359860 A002682 * A370954 A117972 A061532

Adjacent sequences: A073592 A073593 A073594 * A073596 A073597 A073598

Keyword

easy,frac,nonn

Author

Benoit Cloitre, Aug 28 2002

Status

approved