OFFSET
1,4
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..200
PROG
(PARI)
DIK(p, n)={(sum(d=1, n, eulerphi(d)/d*log(subst(1/(1+O(x*x^(n\d))-p), x, x^d))) + ((1+p)^2/(1-subst(p, x, x^2))-1)/2)/2}
seq(n)={my(p=1+O(x)); for(i=1, n\2, p=1+x+x*DIK(x*p, 2*i)); Vec(p+O(x^n))} \\ Andrew Howroyd, Jun 20 2018
CROSSREFS
KEYWORD
nonn,eigen
AUTHOR
STATUS
approved