OFFSET
1,2
COMMENTS
For n < 10 is |a(n)| = A215188(n), but a(10) is different.
FORMULA
E.g.f.: Series_Reversion(arcsin(x^2)-x).
a(n) ~ (-1)^n * (4/sqrt(5)-8/5)^(1/4) * n^(n-1) / (exp(n) * (sqrt(sqrt(5)-2) - arcsin(sqrt(5)-2))^(n-1/2))
MATHEMATICA
Rest[CoefficientList[InverseSeries[Series[ArcSin[x^2]-x, {x, 0, 20}], x], x] * Range[0, 20]!]
CROSSREFS
KEYWORD
sign
AUTHOR
Vaclav Kotesovec, Jan 23 2014
STATUS
approved