This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A104510 #10 Jul 02 2025 16:02:02 %S A104510 0,-1,2,-4,4,-7,4,-5,0,5,-18,23,-46,65,-82,108,-132,152,-164,168,-144, %T A104510 132,-48,-39,212,-365,658,-947,1382,-1800,2394,-2947,3644,-4289,5102, %U A104510 -5687,6392,-6820,7112,-7139,6776,-5836,4338,-2036,-1342,5585,-11392,18513,-27456,37876,-51072,65488,-82982,101898 %N A104510 G.f.: Product_{i>=1} (1 - 2*(-x)^i)/(1 - (-x)^i)^2. %F A104510 a(n) = Sum (k(1)-1)*(k(2)-1)*...*(k(n)-1), where the sum is taken over all (k(1), k(2), ..., k(n)) such that k(1) + 2*k(2) + ... + n*k(n) = n, k(i) >= 0, i=1..n. %F A104510 G.f.: Product_{i>=1} (1 - (-x)^i)^A052823(i). - _James Sellers_, Apr 22 2005 %p A104510 gf:=product((1-2*(-x)^i)/(1-(-x)^i)^2, i=1..100): s:=series(gf, x, 100): for n from 1 to 99 do printf(`%d,`,coeff(s, x, n)) od: # _James Sellers_, Apr 22 2005 %Y A104510 Cf. A000712, A077285. %Y A104510 Cf. A104575. %K A104510 easy,sign %O A104510 1,3 %A A104510 _Vladeta Jovovic_, Apr 19 2005 %E A104510 More terms from _James Sellers_, Apr 22 2005