OFFSET
0,2
FORMULA
a(n) = A083954(2*n) for n>=0.
EXAMPLE
A(x) = 1 + 2*x + 3*x^2 + 4*x^3 + x^4 + 4*x^5 + 3*x^6 + 4*x^7 +...
A(x)^2 = 1 + 4*x + 10*x^2 + 20*x^3 + 27*x^4 + 36*x^5 + 44*x^6 +...
A(x)^2 (mod 8) = 1 + 4*x + 2*x^2 + 4*x^3 + 3*x^4 + 4*x^5 +...
G083954(x) = 1 + 4*x + 2*x^2 + 4*x^3 + 3*x^4 + 4*x^5 + 4*x^6 +...
where G083954(x) is the g.f. of A083954.
PROG
(PARI) {a(n)=local(d=2, m=4, A=1+m*x); for(j=2, d*n, for(k=1, m, t=polcoeff((A+k*x^j+x*O(x^j))^(1/m), j); if(denominator(t)==1, A=A+k*x^j; break))); polcoeff(A, d*n)}
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert G. Wilson v and Paul D. Hanna, Aug 09 2005
STATUS
approved