A121394 - OEIS

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A121394

Column 3 of triangle A121391, where column k of T=A121391 equals column k of T^(k+1) shift down 1 row.

1, 1, 4, 22, 146, 1131, 10120, 104015, 1220957, 16253289, 243450538, 4070466861, 75393600728, 1536160429870, 34213493149270, 828220957918213, 21680478452572459, 610911511290740374, 18453811792850260925

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OFFSET

0,3

COMMENTS

Also equal to column 3 (shifted 1 place) of the matrix 4th power of triangle A121391.

LINKS

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

PROG

(PARI) {a(n)=local(A=Mat(1), B); for(m=1, n+4, B=matrix(m, m); for(i=1, m, for(j=1, i, if(j==i, B[i, j]=1, B[i, j]=(A^j)[i-1, j]); )); A=B); return(A[n+4, 4])}

CROSSREFS

Cf. A121391 (triangle), A121392 (column 1), A121393 (column 2).

Sequence in context: A196795 A278396 A369617 * A005039 A199418 A112898

Adjacent sequences: A121391 A121392 A121393 * A121395 A121396 A121397

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Jul 27 2006

STATUS

approved