OFFSET
0,3
COMMENTS
EXAMPLE
G.f.: A(x) = 1 + x + 2*x^2 + 6*x^3 + 18*x^4 + 61*x^5 + 220*x^6 +...
The g.f. A(x) satisfies:
A(x) = 1 + x*A(x) + x^2*A(x)^3 + x^3*A(x)^2 + x^4*A(x)^6 + x^5*A(x)^7 + x^6*A(x)^5 + x^7*A(x)^4 + x^8*A(x)^12 + x^9*A(x)^13 + x^10*A(x)^15 +...
where the powers of A(x) are given by A003188, which begins:
[0,1,3,2,6,7,5,4,12,13,15,14,10,11,9,8,24,25,27,26,30,31,29,...].
PROG
(PARI) {a(n)=local(A=1+x); for(i=1, n, A=sum(m=0, n, x^m*(A+x*O(x^n))^bitxor(m, m\2))); polcoeff(A, n)}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Jul 01 2011
STATUS
approved