A132692 Column 1 of triangle A132690.

1, 1, -2, 12, -118, 1605, -27816, 585046, -14459138, 410368743, -13146830110, 469123986529, -18447791712945, 792514583941223, -36925394368325295, 1854525584914459755, -99872579714406393286, 5740977285851988017769, -350847888975706702249890

Offset

0,3

Comments

Appears to be essentially a signed version of A121425. - N. J. A. Sloane, Oct 30 2008

Triangle T=A132690 is generated from negative powers of itself such that row n+1 of T = row n of T^(-n) with appended '1' for n>=0 with T(0,0)=1.

Links

Table of n, a(n) for n=0..18.

Prog

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

Crossrefs

Cf. A132690; A132691, A132693, A132694, A121425.

Sequence in context: A009742 A279201 A121425 * A009546 A009748 A212414

Adjacent sequences: A132689 A132690 A132691 * A132693 A132694 A132695

Keyword

sign

Author

Paul D. Hanna, Aug 25 2007

Status

approved