Number of positive integers <= 2^n of form 3 x^2 + 7 y^2.

Terms

a(0) =0a(1) =0a(2) =1a(3) =2a(4) =4a(5) =8a(6) =13a(7) =24a(8) =44a(9) =79a(10) =147a(11) =275a(12) =516a(13) =976a(14) =1859a(15) =3552a(16) =6810a(17) =13102a(18) =25281a(19) =48908a(20) =94819a(21) =184144a(22) =358279a(23) =698183a(24) =1362298a(25) =2661409a(26) =5204770a(27) =10189097a(28) =19964562a(29) =39151220