Numbers m such that all terms in the sequence m, A040115(m), A040115(A040115(m)), ..., 0 are triangular numbers (A000217).

A087598

Numbers m such that all terms in the sequence m, A040115(m), A040115(A040115(m)), ..., 0 are triangular numbers (A000217).

Terms

    a(0) =0a(1) =1a(2) =3a(3) =6a(4) =10a(5) =21a(6) =28a(7) =36a(8) =45a(9) =55a(10) =66a(11) =78a(12) =171a(13) =465a(14) =528a(15) =666a(16) =2211a(17) =4465a(18) =22791a(19) =333336

External references