login
A013183
exp(arctanh(x)+arcsinh(x)) = 1+2*x+4/2!*x^2+9/3!*x^3+24/4!*x^4+105/5!*x^5...
0
1, 2, 4, 9, 24, 105, 630, 4095, 27720, 235305, 2353050, 24792075, 267567300, 3350672325, 46909412550, 682570263375, 10103827734000, 167108397080625, 3007951147451250, 55823919598321875, 1049953727680357500
OFFSET
0,2
FORMULA
E.g.f.: ((x+1)/sqrt(1-x^2))*(x+sqrt(1+x^2)). - Vaclav Kotesovec, Oct 24 2013
a(n) ~ 2*(1+sqrt(2)) * n^n / exp(n). - Vaclav Kotesovec, Oct 24 2013
MATHEMATICA
CoefficientList[Series[Exp[ArcTanh[x]+ArcSinh[x]], {x, 0, 20}], x]* Range[0, 20]! (* Vaclav Kotesovec, Oct 24 2013 *)
CROSSREFS
Sequence in context: A012936 A013091 A013168 * A049963 A368458 A114110
KEYWORD
nonn
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
STATUS
approved