A113984 Column 1 of triangle A113983, also a(n) = [A113983^2](n-1,0) + 1.

1, 2, 3, 5, 9, 19, 47, 137, 465, 1819, 8123, 41077, 233473, 1480947, 10412591, 80634433, 683674833, 6312152355, 63144706755, 681317547509, 7896054343497, 97919789763075, 1294863406981791, 18200820837825481, 271147632138373601

Offset

0,2

Links

Table of n, a(n) for n=0..24.

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[n+2, 2]

Crossrefs

Cf. A113983, A113985 (column 2), A113986 (column 3), A113987 (column 4); A113988 (=A113983^2), A113989.

Sequence in context: A049910 A077643 A123389 * A110542 A101542 A101581

Adjacent sequences: A113981 A113982 A113983 * A113985 A113986 A113987

Keyword

nonn

Author

Paul D. Hanna, Nov 12 2005

Status

approved