OFFSET
0,4
COMMENTS
See triangle A100075 of initial coefficients of successive powers of the e.g.f. for this sequence.
EXAMPLE
List the coefficients of powers of e.g.f. A(x) = Sum_{n>=0} a(n)*x^n/n!:
A(x)^0: [1,__0,0,0,0,0,0,0,0,...],
A(x)^1: [1,1,__1,-3,9,-33,513,-10917,155313,...],
A(x)^2: [1,2,4,__0,0,-36,1080,-17928,181440,...],
A(x)^3: [1,3,9,15,__9,-99,1521,-17631,112401,...],
A(x)^4: [1,4,16,48,96,__-72,1296,-11664,31104,...],
A(x)^5: [1,5,25,105,345,555,__1305,-6705,-6255,...],
A(x)^6: [1,6,36,192,864,2772,6408,__648,-15552,...],...
then for each row n, Sum_{k=0..n} (A(x)^n)_k/k! = [sqrt(5)^n]:
[sqrt(5)^0] = 1 = 1
[sqrt(5)^1] = 1+1 = 2
[sqrt(5)^2] = 1+2+4/2! = 5
[sqrt(5)^3] = 1+3+9/2!+15/3! = 11
[sqrt(5)^4] = 1+4+16/2!+48/3!+96/4! = 25
[sqrt(5)^5] = 1+5+25/2!+105/3!+345/4!+555/5! = 55
[sqrt(5)^6] = 1+6+36/2!+192/3!+864/4!+2772/5!+6408/6! = 125
PROG
(PARI) {a(n)=local(A, C, F, G); if(n==0, A=1, F=sum(k=0, n-1, a(k)*x^k/k!); C=floor(sqrt(5)^n+1/10^15)-sum(k=0, n-1, polcoeff(F^n+x*O(x^k), k, x)); G=sum(k=0, n-1, polcoeff(F^n+x*O(x^k), k, x)*x^k); A=n!*polcoeff((G+C*x^n)^(1/n)+x*O(x^n), n, x)); A}
CROSSREFS
KEYWORD
sign
AUTHOR
Paul D. Hanna, Nov 03 2004
STATUS
approved