cp's OEIS Frontend

A086795 a(n) is the number of terms in the expansion of (x-2y)*(x^2-2y^2)*(x^3-2y^3)*...*(x^n-2y^n).

%I A086795 #3 Sep 15 2012 15:19:13
%S A086795 2,4,7,11,13,21,28,35,42,53,65,74,87,102,117,133,150,168,188,207,228,
%T A086795 251,273,298,323,348,375,404,433,463,494,526,559,592,627,664,701,739,
%U A086795 778,817,858,901,944,988,1032,1079,1126,1174,1222,1273
%N A086795 a(n) is the number of terms in the expansion of (x-2y)*(x^2-2y^2)*(x^3-2y^3)*...*(x^n-2y^n).
%p A086795 A086795 := proc(n)
%p A086795     mul( x^i-2*y^i,i=1..n) ;
%p A086795     expand(%) ;
%p A086795     nops([coeffs(%)]) ;
%p A086795 end proc: # _R. J. Mathar_, Sep 15 2012
%Y A086795 Cf. A086781.
%K A086795 nonn
%O A086795 1,1
%A A086795 Yuval Dekel (dekelyuval(AT)hotmail.com), Aug 05 2003