Numbers k such that the k-th triangular number contains only digits {6,7,8}.

A119231

Numbers k such that the k-th triangular number contains only digits {6,7,8}.

Terms

    a(0) =3a(1) =11a(2) =12a(3) =36a(4) =116a(5) =132a(6) =1163a(7) =1332a(8) =13332a(9) =133332a(10) =1333332a(11) =3941747a(12) =11737707a(13) =13333332a(14) =133333332a(15) =1333333332a(16) =13333333332a(17) =133333333332a(18) =416381478667

External references