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A009310
Expansion of log(1+log(1+tan(x))).
0
0, 1, -2, 9, -51, 384, -3506, 38126, -479770, 6872392, -110410296, 1967181840, -38502498592, 821352161200, -18969587297792, 471608373782864, -12558441874756176, 356636706706414848, -10759204665600245888
OFFSET
0,3
FORMULA
a(n) ~ (n-1)! * (-1)^(n+1) / (arctan(1-exp(-1))^n). - Vaclav Kotesovec, Jan 22 2015
MATHEMATICA
Log[ 1+Log[ 1+Tan[ x ] ] ]
CoefficientList[Series[Log[1 + Log[1 + Tan[x]]], {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 22 2015 *)
CROSSREFS
Sequence in context: A374567 A246464 A355397 * A091319 A193465 A003584
KEYWORD
sign,easy
AUTHOR
EXTENSIONS
Extended with signs by Olivier Gérard, Mar 15 1997
STATUS
approved