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).

2, 4, 7, 11, 13, 21, 28, 35, 42, 53, 65, 74, 87, 102, 117, 133, 150, 168, 188, 207, 228, 251, 273, 298, 323, 348, 375, 404, 433, 463, 494, 526, 559, 592, 627, 664, 701, 739, 778, 817, 858, 901, 944, 988, 1032, 1079, 1126, 1174, 1222, 1273

Offset: 1

Author

Yuval Dekel (dekelyuval(AT)hotmail.com), Aug 05 2003

Keywords

• nonn

Crossrefs

Cf. A086781.

Programs

Maple

A086795 := proc(n)
    mul( x^i-2*y^i,i=1..n) ;
    expand(%) ;
    nops([coeffs(%)]) ;
end proc: # R. J. Mathar, Sep 15 2012