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%I #10 Jun 15 2017 02:17:08
%S 0,1,2,8,32,159,882,5475,37256,276004,2207944,18949677,173475876,
%T 1685805913,17319275430,187443865596,2130493441472,25360318907075,
%U 315370749394134,4088067189914051,55128639891893220,771992274220462744,11207495397779852000
%N Exponentiation of g.f. for Pell numbers.
%F a(-1) = 1, a(n) = Sum_{k=0..n} binomial(n, k) * A000129(k) * a(n-k-1). - _Sean A. Irvine_, Jun 11 2017
%o (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
%Y Cf. A000129.
%K nonn
%O 0,3
%A _N. J. A. Sloane_.