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A006669
Exponentiation of g.f. for Pell numbers.
1
0, 1, 2, 8, 32, 159, 882, 5475, 37256, 276004, 2207944, 18949677, 173475876, 1685805913, 17319275430, 187443865596, 2130493441472, 25360318907075, 315370749394134, 4088067189914051, 55128639891893220, 771992274220462744, 11207495397779852000
OFFSET
0,3
FORMULA
a(-1) = 1, a(n) = Sum_{k=0..n} binomial(n, k) * A000129(k) * a(n-k-1). - Sean A. Irvine, Jun 11 2017
PROG
(PARI) alias(A006669_vec, a6669); a6669=[]; A006669(n)={n<1&&return(-n); if(n>#a6669, a6669=concat(a6669, vector(n-#a6669)), a6669[n]&&return(a6669[n])); a6669[n]=sum(k=0, n, binomial(n, k)*A000129(k)*A006669(n-k-1))} \\ use e.g. A000129=n->imag((quadgen(8)+1)^n). - M. F. Hasler, Jun 15 2017
CROSSREFS
Cf. A000129.
Sequence in context: A131785 A347363 A359398 * A193778 A030804 A319364
KEYWORD
nonn
AUTHOR
STATUS
approved