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A255486
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Number of odd terms in expansion of (1+x+x^3+x^4)^n.
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4
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1, 4, 4, 10, 4, 12, 10, 18, 4, 16, 12, 28, 10, 28, 18, 38, 4, 16, 16, 40, 12, 40, 28, 52, 10, 40, 28, 64, 18, 52, 38, 74, 4, 16, 16, 40, 16, 48, 40, 72, 12, 48, 40, 96, 28, 88, 52, 108, 10, 40, 40, 100, 28, 96, 64, 120, 18, 72, 52, 120, 38
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OFFSET
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0,2
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LINKS
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MAPLE
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r1:=proc(f) local g, n; g:=n->nops(expand(f^n) mod 2); [seq(g(n), n=0..90)]; end;
r1(1+x+x^2+x^3);
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MATHEMATICA
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a[n_] := Count[(List @@ Expand[(1+x+x^3+x^4)^n]) /. x -> 1, _?OddQ]; a[0] = 1;
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PROG
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(PARI) a(n) = {my(pol=(1+x+x^3+x^4)*Mod(1, 2)); subst(lift(pol^n), x, 1); } \\ Michel Marcus, Mar 01 2015
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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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