a(n) = (A242804(n)-9)/12.

Terms

a(0) =17a(1) =11924a(2) =16229a(3) =17177a(4) =22784a(5) =57074a(6) =67304a(7) =114494a(8) =115979a(9) =126377a(10) =132632a(11) =134249a(12) =147899a(13) =156914a(14) =157646a(15) =170537a(16) =170957a(17) =180284a(18) =180329a(19) =194837a(20) =196664a(21) =210209a(22) =242819a(23) =259016a(24) =351812a(25) =358109a(26) =361244a(27) =405509