A109319 Row sums of triangle T=A109316 where T(n,k) = [T^2](n-1,k) + [T^2](n-2,k-1) and T^2 is the matrix square of A109316.

1, 2, 5, 15, 55, 235, 1119, 5775, 31663, 182087, 1087927, 6706823, 42433735, 274403575, 1807700679, 12099813111, 82113733447, 563992581079, 3914861387495, 27429176467703, 193781828188615, 1379223584026967

Offset

0,2

Links

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

Prog

(PARI) {a(n)=local(A=Mat(1), B); for(m=1, n+1, B=matrix(m, m); for(i=1, m, for(j=1, i, if(j==i, B[i, j]=1, if(i==2, B[i, j]=1, B[i, j]=(A^2)[i-1, j]+if(j>1, (A^2)[i-2, j-1]))); )); A=B); return(sum(k=0, n, A[n+1, k+1]))}

Crossrefs

Cf. A109316 (triangle), A109317 (column 0), A109318 (column 2).

Sequence in context: A334154 A009383 A104429 * A059219 A242275 A363200

Adjacent sequences: A109316 A109317 A109318 * A109320 A109321 A109322

Keyword

nonn

Author

Paul D. Hanna, Jul 07 2005

Status

approved