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%I #16 Oct 30 2023 11:36:22
%S 1,1,0,1,1,1,3,7,31,331,12795,4642051,60935796571,283646808320375611,
%T 17285560913056915909539455163,
%U 4902995236325455290013100337511909917402705547
%N a(n) = a(n - 1)*a(n - 2) + a(n - 2)*a(n - 3) + a(n - 1)*a(n - 3).
%C Essentially the same as A074047. [_R. J. Mathar_, Aug 07 2008]
%t a[0] = 0; a[1] = 1; a[2] = 1; a[n_] := a[n] = a[n - 1]*a[n - 2] + a[n - 2]*a[n - 3] + a[n - 1]*a[n - 3] Table[a[n], {n, 0, 15}]
%o (PARI) {f23(x,y,z)=x*y+y*z+z*x;a=[0,1,1]; for(n=1,19,a=concat(a,f23(a[n],a[n+1],a[n+2])));a} \\ _M. F. Hasler_, Jan 01 2013
%Y Cf. A203761 and references therein.
%Y Cf. A074047.
%K nonn
%O -1,7
%A _Roger L. Bagula_, Aug 30 2006
%E Edited by _N. J. A. Sloane_, Oct 08 2006
%E Extended the sequence by prefixing the two values a(0)=a(-1)=1. - _M. F. Hasler_, Jan 01 2013
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