Let {g(n)} be the sequence of rational numbers defined by the recurrence: 256*(n+1)*g(n+1) - 32*(22*n^2+22n+9)*g(n) + 144*n*(4n^2+1)*g*(n-1) - 9*(2n-1)^4*g(n-2) = 0 (n>=0) with g(-2)=g(-1)=0 and g(1)=1. Then a(n) is the numerator of g(n). - Herman Jamke (hermanjamke(AT)fastmail.fm), Feb 18 2008
PROG
(PARI) g=vector(100); g[3]=1; print1("1, "); for(n=1, 30, g[n+3]=(32*(22*(n^2-n)+9)*g[n+2]-144*(n-1)*(4*(n-1)^2+1)*g[n+1]+9*(2*n-3)^4*g[n])/(256*n); print1(numerator(g[n+3])", ")) \\ Herman Jamke (hermanjamke(AT)fastmail.fm), Feb 18 2008