%I #5 Mar 30 2012 18:35:40
%S 1,1,2,2,4,9,15,29,52,96,179,336,640,1218,2338,4507,8706,16874,32808,
%T 63863,124599,243437,476164,932611,1828498,3588303,7047954,13853566,
%U 27250355,53636267,105633670,208154090,410381069,809456768,1597319534
%N Number of positive integers <= 2^n of form x^2 + 19 y^2.
%K nonn
%O 0,3
%A _David W. Wilson_