OFFSET
0,2
LINKS
Vaclav Kotesovec, Table of n, a(n) for n = 0..400
FORMULA
a(k) ~ -k! / (log(2))^(k+1).
For n>0, a(n) = Sum_{k=1..n} A261254(k) * Stirling2(n-1, k-1).
EXAMPLE
A261239(n)/(-3*n!) ~ 1 - 4/n + 2/n^2 - 2/n^3 - 31/n^4 - 288/n^5 - 2939/n^6 - ...
MATHEMATICA
Flatten[{1, Table[Sum[CoefficientList[Assuming[Element[x, Reals], Series[E^(4/x)*x^4/ExpIntegralEi[1/x]^4, {x, 0, 25}]], x][[k+1]] * StirlingS2[n-1, k-1], {k, 1, n}], {n, 1, 25}]}]
CROSSREFS
KEYWORD
sign
AUTHOR
Vaclav Kotesovec, Aug 12 2015
STATUS
approved