OFFSET
1,3
COMMENTS
Compare the g.f. to the following identities:
(1) C(x) = C( x^2 + 2*x*C(x)^2 )^(1/2),
(2) C(x) = C( x^3 + 3*x*C(x)^3 )^(1/3),
where C(x) = x + C(x)^2 is a g.f. of the Catalan numbers (A000108).
More generally, for prime p there exists an integer series G(x) that satisfies: G(x) = G( x^p + p*x*G(x)^p )^(1/p) with G(0)=0, G'(0)=1 (conjecture).
LINKS
Paul D. Hanna, Table of n, a(n) for n = 1..300
EXAMPLE
G.f.: A(x) = x + x^2 + 6*x^3 + 46*x^4 + 391*x^5 + 3519*x^6 + 32844*x^7 + 314364*x^8 + 3065049*x^9 + 30309929*x^10 + 303099290*x^11 + 3058547381*x^12 +...
where A(x)^11 = A( x^11 + 11*x*A(x)^11 ).
RELATED SERIES.
A(x)^11 = x^11 + 11*x^12 + 121*x^13 + 1331*x^14 + 14641*x^15 + 161051*x^16 + 1771561*x^17 + 19487171*x^18 + 214358881*x^19 + 2357947691*x^20 + 25937424601*x^21 + 285311670612*x^22 + 3138428376754*x^23 + 34522712144657*x^24 +...
PROG
(PARI) {a(n) = my(A=x+x^2, X=x+x*O(x^n)); for(i=1, n, A = subst(A, x, x^11 + 11*X*A^11)^(1/11) ); polcoeff(A, n)}
for(n=1, 40, print1(a(n), ", "))
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Apr 16 2016
STATUS
approved