Triangular numbers for which the number of divisors is also a triangular number.

Terms

a(0) =1a(1) =28a(2) =45a(3) =153a(4) =171a(5) =325a(6) =496a(7) =2016a(8) =3321a(9) =4753a(10) =4950a(11) =7260a(12) =7381a(13) =8256a(14) =11628a(15) =13203a(16) =14196a(17) =20100a(18) =29161a(19) =41616a(20) =56953a(21) =64620a(22) =65341a(23) =73536a(24) =76636a(25) =77028a(26) =89676a(27) =90100a(28) =97461a(29) =101475