Numbers k such that the k-th triangular number contains only digits {0,5,6}.

Terms

a(0) =3a(1) =10a(2) =11a(3) =36a(4) =100a(5) =105a(6) =114a(7) =363a(8) =1000a(9) =1095a(10) =1100a(11) =3363a(12) =10000a(13) =11000a(14) =100000a(15) =110000a(16) =1000000a(17) =1100000a(18) =10000000a(19) =11000000a(20) =11541720a(21) =33166430a(22) =33336636a(23) =100000000a(24) =110000000a(25) =1000000000a(26) =1100000000a(27) =3363197899a(28) =3464103363