a(n) is the smallest k such that (k^3 + 1)/(n^3 + 1) is an integer > 1.

Terms

a(0) =3a(1) =5a(2) =19a(3) =49a(4) =17a(5) =26a(6) =295a(7) =107a(8) =649a(9) =153a(10) =323a(11) =69a(12) =145a(13) =719a(14) =3151a(15) =3841a(16) =251a(17) =597a(18) =6499a(19) =362a(20) =8821a(21) =10165a(22) =3527a(23) =1399a(24) =2981a(25) =836a(26) =1063a(27) =21169a(28) =7289a(29) =3254