A104447 Column 1 of triangular matrix A104446.

1, 2, 5, 13, 39, 139, 587, 2897, 16462, 106301, 771313, 6228073, 55494336, 541651873, 5753940704, 66147591142, 818802488476, 10864622564915, 153914784829775, 2319599022540318, 37068215129072522, 626279667948552452

Offset: 0

Author

Paul D. Hanna, Mar 08 2005

Keywords

• nonn

Comments

A104446 equals the square of triangular matrix A104445, read by rows, where X=A104445 satisfies: SHIFT_LEFT_UP(X) = X^2 - X + I.

Crossrefs

Cf. A104446, A091352, A091353.

Programs

PARI

a(n)=local(A=Mat(1),B);for(m=1,n+1,B=A^2-A+A^0; A=matrix(m+1,m+1);for(i=1,m+1, for(j=1,i, if(i<2 || j==i,A[i,j]=1,if(j==1,A[i,j]=1,A[i,j]=B[i-1,j-1]))))); return((A^2)[n+2,2])

Formula

a(n) = A091352(n-1) + A091353(n-1).