A009325 E.g.f.: Expansion of log(1+log(1+x)^2) = 2*x^2/2! -6*x^3/3! +10*x^4/4! -...

0, 0, 2, -6, 10, 20, -232, 252, 12108, -137520, 510672, 6198720, -106090272, 110313216, 20049746208, -350494492320, 1386443717472, 58129858399488, -1210759844215296, -890205571360512, 529981110594263808, -11472138235428595200, 24598100800739059200

Offset

0,3

Links

Alois P. Heinz, Table of n, a(n) for n = 0..175

Formula

a(n) = sum(k=1..n, (2*k)!*stirling1(n,2*k)/k*(-1)^k). - Vladimir Kruchinin, Sep 28 2012

a(n) ~ -2*cos(n*(1+Pi)/2) * (n-1)! / (2-2*cos(1))^(n/2). - Vaclav Kotesovec, Sep 05 2014

Mathematica

With[{nn=30}, CoefficientList[Series[Log[1+Log[1+x]^2], {x, 0, nn}], x]Range[0, nn]!] (* Harvey P. Dale, Mar 06 2013 *)

Crossrefs

Sequence in context: A014279 A050543 A025588 * A308346 A192390 A272967

Adjacent sequences: A009322 A009323 A009324 * A009326 A009327 A009328

Keyword

sign,easy

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Definition clarified by Harvey P. Dale, Mar 06 2013

Status

approved