OFFSET
0,2
LINKS
Andrew Howroyd, Table of n, a(n) for n = 0..50
EXAMPLE
G.f.: A(x) = 1 + 2*x + 30*x^2 + 1988*x^3 + 519862*x^4 +...
A(x)^2 = 1 + 4*x + 64*x^2 + 4096*x^3 + 1048576*x^4 +...+ 4^(n(n+1)/2)*x^n +...
PROG
(PARI) {a(n)=polcoeff(sum(k=0, n, 4^(k*(k+1)/2)*x^k +x*O(x^n))^(1/2), n)}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Jul 14 2009
EXTENSIONS
Terms a(11) and beyond from Andrew Howroyd, Nov 08 2019
STATUS
approved