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A013200
Expansion of e.g.f. log(sec(x)+arctanh(x)).
1
0, 1, 0, 1, 0, 13, -48, 677, -4480, 54937, -471680, 6248713, -65916928, 988579109, -12514310144, 212756765101, -3159842455552, 60179200959793, -1026648500830208, 21632158018229009, -416691460525064192
OFFSET
0,6
LINKS
EXAMPLE
E.g.f. = x+1/3!*x^3+13/5!*x^5-48/6!*x^6+677/7!*x^7...
MAPLE
S:= series(ln(sec(x)+arctanh(x)), x, 51):
seq(coeff(S, x, n)*n!, n=0..50); # Robert Israel, Mar 08 2023
MATHEMATICA
With[{nn=20}, CoefficientList[Series[Log[Sec[x]+ArcTanh[x]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Jan 21 2014 *)
PROG
(PARI) my(x='x+O('x^30)); concat(0, Vec(serlaplace(log(1/cos(x)+atanh(x))))) \\ Michel Marcus, Mar 08 2023
CROSSREFS
Sequence in context: A288746 A220707 A189349 * A156694 A080171 A303680
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
EXTENSIONS
Zero prepended to terms by Harvey P. Dale, Jan 21 2014
STATUS
approved