A127128 Column 1 of triangle A127126.

1, 2, 9, 54, 412, 3834, 42131, 533558, 7645065, 122177706, 2153221318, 41464853266, 865908079369, 19484990264956, 469910189792853, 12089047867952058, 330423404118495975, 9561012695542004496

Offset

1,2

Comments

Convolution square of A127131.

Links

G. C. Greubel, Table of n, a(n) for n = 1..80

Mathematica

T[n_, k_]:= T[n, k]= If[k==n, 1, Coefficient[(1 +x*Sum[x^(r-k-1)*Sum[T[r, c], {c, k+1, r}], {r, k+1, n}] + x^(n+1))^(k+1), x, n-k]]; Table[T[n, 1], {n, 1, 20}] (* G. C. Greubel, Jan 28 2020 *)

Crossrefs

Cf. A127126; A127131; other columns: A127127, A127129, A127130.

Sequence in context: A307442 A222014 A321974 * A353255 A254795 A064151

Adjacent sequences: A127125 A127126 A127127 * A127129 A127130 A127131

Keyword

nonn

Author

Paul D. Hanna, Jan 05 2007

Status

approved