Centered hexamorphic numbers: the k-th centered hexagonal number, 3k(k-1)+1, ends in k.

Terms

a(0) =1a(1) =7a(2) =17a(3) =51a(4) =67a(5) =167a(6) =251a(7) =417a(8) =501a(9) =667a(10) =751a(11) =917a(12) =1251a(13) =1667a(14) =5001a(15) =5417a(16) =6251a(17) =6667a(18) =10417a(19) =16667a(20) =50001a(21) =56251a(22) =60417a(23) =66667a(24) =166667a(25) =260417a(26) =406251a(27) =500001a(28) =666667a(29) =760417