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

Terms

a(0) =0a(1) =1a(2) =1a(3) =2a(4) =4a(5) =8a(6) =15a(7) =27a(8) =51a(9) =93a(10) =174a(11) =329a(12) =620a(13) =1177a(14) =2250a(15) =4308a(16) =8286a(17) =15961a(18) =30871a(19) =59792a(20) =116083a(21) =225754a(22) =439666a(23) =857554a(24) =1674630a(25) =3273944a(26) =6407147a(27) =12550615a(28) =24605525a(29) =48277287