A135882 Column 1 of triangle A135880.

1, 2, 7, 34, 215, 1698, 16220, 182714, 2378780, 35219202, 585245185, 10797322816, 219163958124, 4856832298391, 116735215192864, 3025759884533190, 84155831914971391, 2500599947944218716, 79072271422935678302

Offset: 0

Author

Paul D. Hanna, Dec 15 2007

Keywords

• nonn

Examples

			Equals column 1 of triangle P=A135880:
1;
1, 1;
2, 2, 1;
6, 7, 3, 1;
25, 34, 15, 4, 1;
138, 215, 99, 26, 5, 1;
970, 1698, 814, 216, 40, 6, 1; ...
where column k of P^2 equals column 0 of P^(2k+2)
such that column 0 of P^2 equals column 0 of P shift left.
		

Links

• Paul D. Hanna, Table of n, a(n) for n = 0..79

Crossrefs

Cf. A135880; other columns: A135881, A135883, A135884.

Programs

PARI

{a(n)=local(P=Mat(1),R,PShR);if(n==0,1,for(i=0,n, PShR=matrix(#P,#P, r,c, if(r>=c,if(r==c,1,if(c==1,0,P[r-1,c-1]))));R=P*PShR; R=matrix(#P+1, #P+1, r,c, if(r>=c, if(r<#P+1,R[r,c], if(c==1,(P^2)[ #P,1],(P^(2*c-1))[r-c+1,1])))); P=matrix(#R, #R, r,c, if(r>=c, if(r<#R,P[r,c], (R^c)[r-c+1,1]))));P[n+2,2])}

Extensions

Error in entries (false comma) corrected by N. J. A. Sloane, Jan 23 2008