OFFSET
0,2
FORMULA
E.g.f.: Sum_{n>=0} log(1+x)^n * (1-x)^(2^n) / n!.
E.g.f.: Sum_{n>=0} log(1-x)^n * (1+x)^(2^n) / n!.
EXAMPLE
E.g.f: A(x) = 1 - 4*x^2/2! + 60*x^4/4! - 4560*x^6/6! + 1617840*x^8/8! - 2466858240*x^10/10! + 15838238465280*x^12/12! + ...
where
A(x) = (1-x) + log(1+x)*(1-x)^2 + log(1+x)^2*(1-x)^4/2! + log(1+x)^3*(1-x)^8/3! + log(1+x)^4*(1-x)^16/4! + ...
also
A(x) = (1+x) + log(1-x)*(1+x)^2 + log(1-x)^2*(1+x)^4/2! + log(1-x)^3*(1+x)^8/3! + log(1-x)^4*(1+x)^16/4! + ...
RELATED SERIES.
arccos(A(x)) = 4*x/2 - 44*x^3/(2^3*3!) + 8836*x^5/(2^5*5!) - 10920780*x^7/(2^7*7!) + 58866344964*x^9/(2^9*9!) - 1318980481299180*x^11/(2^11*11!) + ...
PROG
(PARI) {a(n) = my(A = sum(m=0, 2*n, log(1+x +O(x^(2*n+1)))^m/m! * (1-x +O(x^(2*n+1)))^(2^m) ) ); (2*n)!*polcoeff(A, 2*n)}
for(n=0, 15, print1(a(n), ", "))
CROSSREFS
KEYWORD
sign
AUTHOR
Paul D. Hanna, Feb 01 2021
STATUS
approved