On Dec 26, 2007 1:40 PM, David W. Wilson <wilson.d at anseri.com> wrote: > > Can anyone reconcile either of the formulae on A000033 with the values? For the first formula (the coefficient of t^2 in ....), I get the same values as in the online entry. For the second formula, all that's missing is the (-1)^k factor. -- Mitch Harris