OFFSET
0,4
MATHEMATICA
nn = 19; c = (A000088 = Table[NumberOfGraphs[n], {n, 0, nn}]; f[x_] = 1 - Product[1/(1 - x^k)^a[k], {k, 1, nn}];
a[0] = a[1] = a[2] = 1; coes = CoefficientList[Series[f[x], {x, 0, nn}], x]; sol = First[Solve[Thread[Rest[coes + A000088] == 0]]]; Table[a[n], {n, 0, nn}] /. sol); p = Product[1 + c[[n + 1]] x^n, {n, 1, nn}]; CoefficientList[ Series[p, {x, 0, nn}], x]
(* The Mma code for c in the above is given by Jean-François Alcover in A001349. *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Geoffrey Critzer, Apr 12 2012
STATUS
approved