Number of positive integers <= 2^n of form x^2 + 11 y^2.

Terms

a(0) =1a(1) =1a(2) =2a(3) =2a(4) =7a(5) =10a(6) =19a(7) =34a(8) =60a(9) =112a(10) =214a(11) =400a(12) =761a(13) =1450a(14) =2774a(15) =5341a(16) =10322a(17) =19992a(18) =38823a(19) =75551a(20) =147250a(21) =287503a(22) =562102a(23) =1100266a(24) =2155940a(25) =4228715a(26) =8301245a(27) =16309119a(28) =32064447a(29) =63082900