Index numbers for palindromic hexagonal numbers.

Terms

a(0) =0a(1) =1a(2) =2a(3) =6a(4) =39a(5) =55a(6) =87a(7) =182a(8) =556a(9) =644a(10) =797a(11) =917a(12) =1593a(13) =1685a(14) =25141a(15) =51425a(16) =55556a(17) =83527a(18) =810311a(19) =1620213a(20) =1853942a(21) =5555556a(22) =17352586a(23) =17835196a(24) =25004441a(25) =91071921a(26) =170563673a(27) =181737182a(28) =184252876a(29) =507354403