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A142471
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a(0) = a(1) = 0; thereafter a(n) = a(n-1)*a(n-2) + 2.
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2
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0, 0, 2, 2, 6, 14, 86, 1206, 103718, 125083910, 12973452977382, 1622770224612082123622, 21052933202100473722674133293917606, 34164073141115747076263787631563122725393126176374288934
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OFFSET
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0,3
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LINKS
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FORMULA
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a(n) ~ c^(phi^n), where c = 1.278178162398588325773605473403497130099080978627235683548955136178125... and phi = A001622 = (1+sqrt(5))/2 is the golden ratio. - Vaclav Kotesovec, May 21 2015
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MAPLE
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a:= proc(n) option remember;
if n<2 then 0
else a(n-1)*a(n-2) + 2
fi; end:
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MATHEMATICA
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a[0] = a[1] = 0; a[n_] := a[n-1] a[n-2] + 2; Table[a[n], {n, 0, 15}] (* T. D. Noe, Nov 14 2011 *)
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PROG
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(Magma) I:=[0, 0]; [n le 2 select I[n] else Self(n-1)*Self(n-2)+2: n in [1..15]]; // Vincenzo Librandi, Nov 14 2011
(Sage)
def a(n): return 0 if n<2 else a(n-1)*a(n-2) + 2
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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