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A185626
Column 1 of triangle A185624.
3
1, 2, 7, 28, 142, 913, 7244, 69004, 771359, 9933242, 145148660, 2376879719, 43167728519, 861914166441, 18779307089740, 443624137266205, 11299168270825627, 308780443524256478, 9014690419440269085, 280081388252523565158, 9229143937723290061482
OFFSET
0,2
COMMENTS
Triangle A185624 equals the matrix square of triangle R = A185620, which satisfies: R^3 - R^2 + I = R shifted left one column.
PROG
(PARI) {a(n)=local(A=Mat(1), B); for(m=1, n+1, 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^2)[n+2, 2])}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Sep 07 2011
STATUS
approved