OFFSET
0,2
COMMENTS
Limit n->infinity a(n)^(1/n) = 4.
LINKS
Vaclav Kotesovec, Table of n, a(n) for n = 0..500
Vaclav Kotesovec, Graph a(n)/4^n
MATHEMATICA
Table[2^(2*n) * SeriesCoefficient[Product[1/(1-x^k)^(2^(-k)), {k, 1, n}], {x, 0, n}], {n, 0, 30}]
Table[4^n * (CoefficientList[Series[Exp[Sum[x^k/(2*k*(1-x^k/2)), {k, 1, n}]], {x, 0, n}], x])[[n+1]], {n, 0, 30}] (* faster *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Vaclav Kotesovec, Mar 14 2015
STATUS
approved