A187542 Convolutions of the central Lah numbers (A187535).

1, 4, 76, 2544, 123696, 7942080, 635633280, 61009159680, 6831940227840, 874493448514560, 125946241018214400, 20156433977646489600, 3548609812373223628800, 681555522002874494976000, 141810253720479017017344000

Offset

0,2

Links

Vaclav Kotesovec, Table of n, a(n) for n = 0..300

Formula

a(n) = sum(L(k)L(n-k),k=0..n), where L(n) is a central Lah number.

a(n) ~ n! * 16^n / (Pi*n). - Vaclav Kotesovec, Oct 06 2019

Maple

a := n -> if n=0 then 1 else binomial(2*n-1, n-1)*(2*n)!/n! fi;
seq(sum(a(k)*a(n-k), k=0..n), n=0..12);

Mathematica

a[n_] := If[n == 0, 1, Binomial[2n - 1, n - 1](2n)!/n!]
Table[Sum[a[k]a[n - k], {k, 0, n}], {n, 0, 20}]

Prog

(Maxima) a(n) := if n=0 then 1 else binomial(2*n-1, n-1)*(2*n)!/n!;
makelist(sum(a(k)*a(n-k), k, 0, n), n, 0, 12);

Crossrefs

Cf. A187536, A008297, A111596, A187536, A187538, A187539, A187540, A187543, A187544, A187545, A187546, A187547, A187548.

Sequence in context: A144210 A220793 A220958 * A364111 A009631 A012020

Adjacent sequences: A187539 A187540 A187541 * A187543 A187544 A187545

Keyword

nonn,easy

Author

Emanuele Munarini, Mar 11 2011

Status

approved