A113994 Column 2 of triangle A113993, also equals column 0 of A113983^3.

1, 3, 9, 27, 89, 327, 1353, 6303, 32953, 192395, 1247473, 8931643, 70221841, 603040399, 5628477521, 56832554399, 618172840753, 7214736795987, 90023735419577, 1196943617218715, 16905957430843689, 252946811300548119

Offset

0,2

Links

Table of n, a(n) for n=0..21.

Example

A113983^3, the matrix cube of triangle A113983, begins:
1;
3,1;
9,6,1;
27,27,9,1;
89,117,57,12,1;
327,529,333,99,15,1;
1353,2583,1965,735,153,18,1;
6303,13815,12185,5393,1383,219,21,1;
32953,81321,80865,40785,12169,2337,297,24,1; ...

Prog

(PARI) a(n)=local(A, B); A=Mat(1); for(m=2, n+2, B=matrix(m, m); for(i=1, m, for(j=1, i, if(i<3 || j==1 || j==i, B[i, j]=1, B[i, j]=A[i-1, j-1]+(A^2)[i-2, j-1] ); )); A=B); (A^3)[n+1, 1]

Crossrefs

Cf. A113993, A113989 (column 1), A113995 (column 3), A113996 (column 4), A113997 (row sums); A113983.

Sequence in context: A179263 A147242 A148924 * A302860 A217639 A328080

Adjacent sequences: A113991 A113992 A113993 * A113995 A113996 A113997

Keyword

nonn

Author

Paul D. Hanna, Nov 12 2005

Status

approved