%I #5 Mar 20 2015 03:10:16
%S 3,96,768,6144,49152,393216,3145728,25165824,201326592,1610612736,
%T 12884901888,103079215104,824633720832,6597069766656,52776558133248,
%U 422212465065984,3377699720527872,27021597764222976,216172782113783808
%N Denominator of (3*2^(n-1) - 1)*integral_{x=0 to 1/(4^n)}1-sqrt x dx.
%F a(n) = 12*8^(n-1) = 12*A001018 for n>1.
%e E.g., I(3)=11/768. The numerator is b(n) = 3*2^(n-1) - 1. E.g., b(3)=11.
%t f[n_] := Denominator[(3*2^(n - 1) - 1)*Integrate[1 - Sqrt[x], {x, 0, 1/4^n}]]; Table[ f[n], {n, 19}] (* _Robert G. Wilson v_ *)
%K nonn,easy
%O 1,1
%A Al Hakanson (hawkuu(AT)excite.com), Apr 30 2004
%E Edited, corrected and extended by _Robert G. Wilson v_, May 08 2004