A372698 E.g.f. A(x) satisfies A(A(A(x))) = (-1/3) * log(1 - 3*x).

0, 1, 1, 3, 15, 103, 882, 8913, 103227, 1359162, 20445228, 349712568, 6547495464, 126821768922, 2557843463769, 63897480940509, 2095074190660212, 53541090460596240, -326496349115947710, -34640510429479259916, 9272999532484623258036

Offset

0,4

Links

Table of n, a(n) for n=0..20.

Formula

Define the sequence b(n,m) as follows. If n<m, b(n,m) = 0, else if n=m, b(n,m) = 1, otherwise b(n,m) = 1/3 * ( 3^(n-m) * |Stirling1(n,m)| - Sum_{l=m+1..n-1} (b(n,l) + Sum_{k=l..n} b(n,k) * b(k,l)) * b(l,m) ). a(n) = b(n,1).

Crossrefs

Cf. A209519, A220112, A372747.

Sequence in context: A123184 A079486 A245118 * A343884 A358738 A331689

Adjacent sequences: A372694 A372695 A372696 * A372699 A372700 A372701

Keyword

sign

Author

Seiichi Manyama, May 11 2024

Status

approved