Triangular numbers whose sum of divisors is also a triangular number.

Terms

a(0) =1a(1) =36a(2) =45a(3) =23220a(4) =105111a(5) =135460a(6) =2492028a(7) =5286126a(8) =6604795a(9) =14308575a(10) =45025305a(11) =50516326a(12) =54742416a(13) =99017628a(14) =108125865a(15) =152486916a(16) =386767578a(17) =1083567628a(18) =1561818105a(19) =3169234305a(20) =5005551540a(21) =5718242211a(22) =6125307903a(23) =6479715880