%I A104631
%S A104631 0,1,4,18,80,365,1686,7875,37080,175725,837100,4004770,19227924,
%T A104631 92599533,447118140,2163837030,10492874384,50972030189,248000853348,
%U A104631 1208335275170,5894873067200,28791371852145,140768761906190
%N A104631 Coefficient of x^(2n+1) in the expansion of (1+x+x^2+x^3+x^4)^n.
%C A104631 In the triangle of pentanomial coefficients, these numbers are in the 
               column next to the central pentanomial coefficients, A005191. Note 
               that for n>0, n divides a(n). This divisibility property is also 
               true for the triangle of trinomial coefficients, A027907, but apparently 
               for no other triangle of m-nomial coefficients. The quotient a(n)/
               n is in A104632.
%t A104631 f=1; Table[f=Expand[f(x^4+x^3+x^2+x+1)]; Coefficient[f, x, 2n+1], {n, 
               30}]
%Y A104631 Cf. A035343 (triangle of pentanomial coefficients).
%Y A104631 Sequence in context: A037965 A045902 A090017 this_sequence A106391 A063881 
               A100192
%Y A104631 Adjacent sequences: A104628 A104629 A104630 this_sequence A104632 A104633 
               A104634
%K A104631 easy,nonn
%O A104631 0,3
%A A104631 T. D. Noe (noe(AT)sspectra.com), Mar 17 2005