Numbers of form x^2 + 9 y^2.

Terms

a(0) =0a(1) =1a(2) =4a(3) =9a(4) =10a(5) =13a(6) =16a(7) =18a(8) =25a(9) =34a(10) =36a(11) =37a(12) =40a(13) =45a(14) =49a(15) =52a(16) =58a(17) =61a(18) =64a(19) =72a(20) =73a(21) =81a(22) =82a(23) =85a(24) =90a(25) =97a(26) =100a(27) =106a(28) =109a(29) =117