Number of positive integers <= 2^n of form 6 x^2 + 9 y^2.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =3a(5) =4a(6) =10a(7) =15a(8) =30a(9) =51a(10) =97a(11) =177a(12) =334a(13) =621a(14) =1182a(15) =2243a(16) =4278a(17) =8203a(18) =15779a(19) =30446a(20) =58882a(21) =114125a(22) =221636a(23) =431155a(24) =840041a(25) =1638853a(26) =3201255a(27) =6259884a(28) =12253156a(29) =24006205