Triangular numbers whose sum of divisors is an oblong number.

Terms

a(0) =6a(1) =28a(2) =55a(3) =496a(4) =666a(5) =780a(6) =1540a(7) =2145a(8) =6441a(9) =6903a(10) =8128a(11) =15051a(12) =21736a(13) =36585a(14) =44551a(15) =232903a(16) =234955a(17) =644680a(18) =2258875a(19) =3186550a(20) =3462396a(21) =6211050a(22) =22174470a(23) =33550336a(24) =48437403a(25) =62591266a(26) =107538445a(27) =134898525a(28) =153554050a(29) =624157446