Numbers k such that the k-th triangular number contains only digits {4,5,6}.

Terms

a(0) =3a(1) =9a(2) =10a(3) =11a(4) =30a(5) =36a(6) =94a(7) =96a(8) =105a(9) =114a(10) =305a(11) =1043a(12) =2988a(13) =3303a(14) =3363a(15) =11363a(16) =3021769a(17) =3054388a(18) =10627009a(19) =33330030a(20) =33330036a(21) =33336636a(22) =94302243a(23) =115470036a(24) =305177471a(25) =336352955885