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A013192
Expansion of e.g.f. log(cosh(x) + arctanh(x)).
1
0, 1, 0, 1, -4, 33, -168, 1377, -9504, 99649, -930560, 11796673, -137207552, 2017677153, -28086102016, 471591223841, -7659623550976, 144742585812609, -2686461109796864, 56447611418620289
OFFSET
0,5
EXAMPLE
x + 1/3!*x^3 - 4/4!*x^4 + 33/5!*x^5 - 168/6!*x^6 ...
MATHEMATICA
With[{nn=20}, CoefficientList[Series[Log[Cosh[x]+ArcTanh[x]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Feb 06 2019 *)
CROSSREFS
Sequence in context: A095671 A278671 A273676 * A273700 A273708 A097705
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
EXTENSIONS
a(0)=0 inserted and title improved by Sean A. Irvine, Aug 01 2018
STATUS
approved