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A202366
Approximate series expansion of arccosh(exp(3*x) - sin(3*x))
1
0, 6, 18, -36, -360, -1350, 27162, 337608, -606528, -90432450, -880859934, 18455713503, 693789107544, 1701104157090, -385899715094310, -8961561593356464, 131483054194960485, 11226865165557040813, 130224770734566143291, -10087278971257481285822
OFFSET
0,2
COMMENTS
Inspired by the Demichel sequences.
Coefficients are multiplied by (n+1)! and rounded to the nearest integer. First fraction occurs at degree 11 ( 18455713503 = round(129189994524/7) ).
LINKS
EXAMPLE
arccosh(exp(3*x) - sin(3*x)) = 6*x/2! + 18*x^2/3! - 36*x^3/4! + ...
MATHEMATICA
Round[Table[(i+1)!, {i, 0, 20}]*CoefficientList[Assuming[x > 0, Series[ArcCosh[Exp[3 x] - Sin[3 x]], {x, 0, 20}]], x]]
CROSSREFS
Sequence in context: A225384 A276480 A180438 * A185223 A299272 A101853
KEYWORD
sign
AUTHOR
Olivier Gérard, Dec 18 2011
STATUS
approved