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A121429 Main diagonal of rectangular table A121428. 2
1, 2, 18, 250, 4520, 99351, 2556806, 75190410, 2483617140, 90955908010, 3655774038653, 159938142409890, 7564604603286913, 384576889110665055, 20912407157570989950, 1211142337261176799610, 74427504634177621877538 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..16.

FORMULA

a(n) = [A121412^(n+1)](n+2,2) for n>=0; i.e., the (n+1)-th term of column 2 in matrix power A121412^(n+1).

PROG

(PARI) {a(n)=local(H=Mat(1), B); for(m=1, n+3, B=matrix(m, m); for(i=1, m, for(j=1, i, if(j==i, B[i, j]=1, B[i, j]=(H^i)[i-1, j]); )); H=B); return((H^(n+1))[n+3, 3])}

CROSSREFS

Cf. A121428, A121412.

Sequence in context: A117514 A138437 A265452 * A337775 A276364 A109517

Adjacent sequences:  A121426 A121427 A121428 * A121430 A121431 A121432

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Aug 26 2006

STATUS

approved

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Last modified October 15 21:38 EDT 2021. Contains 348034 sequences. (Running on oeis4.)