A157316 G.f.: A(x) = tanh( Sum_{n>=0} 2^((2n+1)^2) * x^(2n+1)/(2n+1) ), with zero terms omitted.
2, 168, 6710208, 80421395017344, 268650181814894062310400, 241677817414364648836194235222953984, 57560679870262286682598360350282651217048664506368
Offset: 0
Keywords
Examples
G.f.: A(x) = 2*x + 168*x^3 + 6710208*x^5 + 80421395017344*x^7 + ... arctanh(A(x)) = 2*x + 2^9*x^3/3 + 2^25*x^5/5 + 2^49/7*x^7 + ...
Crossrefs
Cf. A157315.
Programs
-
PARI
{a(n)=polcoeff(tanh(sum(m=0,n,2^((2*m+1)^2)*x^(2*m+1)/(2*m+1))+O(x^(2*n+2))),2*n+1)}
Comments