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A024277
E.g.f.: log(1+tanh(x)*tan(x))/2 (even powers only).
1
0, 1, -6, 176, -8176, 691456, -86186496, 15358324736, -3667315849216, 1135407181398016, -441731548179726336, 211079248633366839296, -121507103129359646457856, 82940335057202543199256576
OFFSET
0,3
EXAMPLE
log(1+tanh(x)*tan(x))/2 = 1/2*x^2 - 1/4*x^4 + 11/45*x^6 - 73/360*x^8 +- ... .
MATHEMATICA
Log[ 1+Tanh[ x ]*Tan[ x ]]/2 (* Even Part *)
CROSSREFS
Cf. A009398.
Cf. A101921.
Sequence in context: A318538 A071095 A134632 * A012177 A012227 A012152
KEYWORD
sign
AUTHOR
EXTENSIONS
Extended with signs Mar 1997
STATUS
approved