OFFSET
0,3
FORMULA
EXAMPLE
2^0 = 1;
2^1 = 1 + 1;
2^2 = 1 + 1*2 + (1/4)*2^2;
2^3 = 1 + 1*3 + (1/4)*3^2 + (7/108)*3^3;
2^4 = 1 + 1*4 + (1/4)*4^2 + (7/108)*4^3 + (77/6912)*4^4.
Initial fractional coefficients are:
395159/2332800000, 31824093937/1921161110400000,
44855117331581/31476303632793600000, ... }.
PROG
(PARI) {a(n)=denominator(sum(k=0, n, 2^k*(matrix(n+1, n+1, r, c, if(r>=c, (r-1)^(c-1)))^-1)[n+1, k+1]))}
CROSSREFS
KEYWORD
nonn,frac
AUTHOR
Paul D. Hanna, May 10 2005
STATUS
approved