Concatenation of n^3 and 7.

Terms

a(0) =17a(1) =87a(2) =277a(3) =647a(4) =1257a(5) =2167a(6) =3437a(7) =5127a(8) =7297a(9) =10007a(10) =13317a(11) =17287a(12) =21977a(13) =27447a(14) =33757a(15) =40967a(16) =49137a(17) =58327a(18) =68597a(19) =80007a(20) =92617a(21) =106487a(22) =121677a(23) =138247a(24) =156257a(25) =175767a(26) =196837a(27) =219527a(28) =243897a(29) =270007