Number of positive integers <= 2^n of form 2 x^2 + 5 y^2.

Terms

a(0) =0a(1) =1a(2) =1a(3) =4a(4) =5a(5) =11a(6) =20a(7) =36a(8) =65a(9) =119a(10) =218a(11) =412a(12) =770a(13) =1466a(14) =2784a(15) =5322a(16) =10226a(17) =19691a(18) =38048a(19) =73665a(20) =142927a(21) =277822a(22) =540851a(23) =1054502a(24) =2058507a(25) =4023164a(26) =7871226a(27) =15414517a(28) =30213010a(29) =59266164