Loeschian numbers: numbers of the form x^2 + xy + y^2; norms of vectors in A2 lattice.

Terms

a(0) =0a(1) =1a(2) =3a(3) =4a(4) =7a(5) =9a(6) =12a(7) =13a(8) =16a(9) =19a(10) =21a(11) =25a(12) =27a(13) =28a(14) =31a(15) =36a(16) =37a(17) =39a(18) =43a(19) =48a(20) =49a(21) =52a(22) =57a(23) =61a(24) =63a(25) =64a(26) =67a(27) =73a(28) =75a(29) =76