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A009288
Expansion of exp(x)/cos(log(1+x)).
0
1, 1, 2, 1, 11, -39, 356, -3023, 30841, -349979, 4422846, -61445339, 931259427, -15288729819, 270290509256, -5119527465219, 103428161877041, -2220041987184023, 50453882091213146, -1210316349687219159
OFFSET
0,3
FORMULA
a(n) ~ n! * exp(-1 + exp(-Pi/2)) / ((exp(Pi/2)-1) * (exp(-Pi/2)-1)^n). - Vaclav Kotesovec, Jan 22 2015
MATHEMATICA
Exp[ x ]/Cos[ Log[ 1+x ] ]
CoefficientList[Series[E^x*Sec[Log[1 + x]], {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 22 2015 *)
CROSSREFS
Sequence in context: A012904 A013015 A012900 * A322513 A082272 A107049
KEYWORD
sign,easy
AUTHOR
EXTENSIONS
Extended with signs by Olivier Gérard, Mar 15 1997
STATUS
approved