A086817 a(n) is the number of terms in the expansion of (x+y-z)*(x^2+y^2-z^2)*(x^3+y^3-z^3)*...*(x^n+y^n-z^n).

3, 9, 22, 48, 102, 182, 328, 566, 910, 1396, 2025, 2882, 3976, 5304, 7002, 9071, 11475, 14444, 17886, 21896, 26531, 31880, 37947, 44899, 52657, 61500, 71406, 82383, 94592, 108097, 123017, 139401, 157439, 177134, 198634, 221962, 247378, 274767, 304483, 336533, 371083, 408168, 447944, 490614, 536208

Offset: 1

Author

Yuval Dekel (dekelyuval(AT)hotmail.com), Aug 06 2003

Keywords

• nonn

Crossrefs

Cf. A086796.

Programs

Maple

P:= 1;
for n from 1 to 90 do
  P:= expand(P*(x^n+y^n-z^n));
  A[n]:= nops(P);
od:
seq(A[n],n=1..90); # Robert Israel, Apr 14 2017

Mathematica

Table[Length[Expand[Times@@Table[x^n+y^n-z^n,{n,i}]]],{i,50}] (* Harvey P. Dale, Oct 02 2018 *)

Extensions

a(12)-a(45) from Robert Israel, Apr 14 2017