A185630 - OEIS

A185630

Column 1 of triangle A185628.

1, 3, 12, 55, 315, 2243, 19378, 198363, 2358860, 32060736, 491393909, 8398281337, 158541018923, 3279307650137, 73808041476439, 1796794875356409, 47063878147374980, 1320276655048586177, 39504980013582635300, 1256210676237601811305, 42313074100060933324771

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OFFSET

0,2

COMMENTS

Triangle A185628 equals the matrix cube of triangle R = A185620, which satisfies: R^3 - R^2 + I = R shifted left one column.

LINKS

Table of n, a(n) for n=0..20.

PROG

(PARI) {a(n)=local(A=Mat(1), B); for(m=1, n+2, B=A^3-A^2+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^3)[n+2, 2])}

CROSSREFS

Cf. A185620, A185628, A185629, A185631.

Sequence in context: A263533 A064314 A362085 * A284843 A107318 A176281

Adjacent sequences: A185627 A185628 A185629 * A185631 A185632 A185633

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Sep 07 2011

STATUS

approved