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 A121810 a(n) = a(n - 1)*a(n - 2) + a(n - 2)*a(n - 3) + a(n - 1)*a(n - 3). 3
 1, 1, 0, 1, 1, 1, 3, 7, 31, 331, 12795, 4642051, 60935796571, 283646808320375611, 17285560913056915909539455163, 4902995236325455290013100337511909917402705547 (list; graph; refs; listen; history; text; internal format)
 OFFSET -1,7 COMMENTS Essentially the same as A074047. [R. J. Mathar, Aug 07 2008] LINKS Table of n, a(n) for n=-1..14. MATHEMATICA 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}] PROG (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 CROSSREFS Cf. A203761 and references therein. Cf. A074047. Sequence in context: A277028 A156895 A074047 * A081475 A123212 A213437 Adjacent sequences: A121807 A121808 A121809 * A121811 A121812 A121813 KEYWORD nonn AUTHOR Roger L. Bagula, Aug 30 2006 EXTENSIONS Edited by N. J. A. Sloane, Oct 08 2006 Extended the sequence by prefixing the two values a(0)=a(-1)=1. - M. F. Hasler, Jan 01 2013 STATUS approved

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Last modified February 21 16:55 EST 2024. Contains 370237 sequences. (Running on oeis4.)