OFFSET
1,1
COMMENTS
Normalized Delta generates Ramanujan tau function.
LINKS
B. Brent, Quadratic Minima and Modular Forms, Experimental Mathematics, v.7 no.3, 257-274.
EXAMPLE
(\tau(1)q+\tau(2)q^2+...)^(-1)=q^(-1)+24+...
MATHEMATICA
a[n_] := (delta = Series[ q*Product[ (1-q^k)^24, {k, 1, n}] , {q, 0, n+1}]; SeriesCoefficient[ Series[ delta^-n, {q, 0, 0}], 0]); Table[a[n], {n, 1, 13}] (* Jean-François Alcover, Feb 20 2012 *)
CROSSREFS
KEYWORD
easy,nice,nonn
AUTHOR
Barry Brent (barryb(AT)primenet.com)
STATUS
approved