A135890 - OEIS

A135890

Column 1 of triangle A135888, which equals the matrix cube of triangle A135880; also equals column 1 of triangle A135895.

1, 6, 39, 300, 2741, 29380, 363922, 5135894, 81557270, 1441771540, 28114817877, 600012111858, 13919315033624, 348932593149877, 9403371859278914, 271183690566871863, 8335374900994682248, 272083236017290793444

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OFFSET

0,2

LINKS

Table of n, a(n) for n=0..17.

PROG

(PARI) {a(n)=local(P=Mat(1), R, PShR); if(n==0, 1, for(i=0, n+1, 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^3)[n+2, 2])}

CROSSREFS

Cf. A135888, A135889; A135880, A135895.

Sequence in context: A009018 A289996 A335344 * A067273 A187117 A137972

Adjacent sequences: A135887 A135888 A135889 * A135891 A135892 A135893

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Dec 15 2007

STATUS

approved