Indices of the least triangular numbers (A000217) for which three consecutive triangular numbers sum to a perfect square (A000290).

A165517

Indices of the least triangular numbers (A000217) for which three consecutive triangular numbers sum to a perfect square (A000290).

Terms

    a(0) =0a(1) =5a(2) =14a(3) =63a(4) =152a(5) =637a(6) =1518a(7) =6319a(8) =15040a(9) =62565a(10) =148894a(11) =619343a(12) =1473912a(13) =6130877a(14) =14590238a(15) =60689439a(16) =144428480a(17) =600763525a(18) =1429694574a(19) =5946945823a(20) =14152517272a(21) =58868694717a(22) =140095478158a(23) =582740001359

External references