A119041 - OEIS

%I #10 Mar 27 2023 22:36:36

%S 1,6,10,66,666,10011,16110,66066,600060,6601161,10006101,11066160,

%T 660061611,1001661661,1061660160,1100016060,1660061010,1001000010660,

%U 1066006600011,10010000160006,106001000601616,60660116660011611,1660616006066010601060060

%N Triangular numbers composed of digits {0,1,6}.

%H Giovanni Resta, <a href="http://www.numbersaplenty.com/tr/tr016.html">Tridigital Triangular Numbers</a>

%F a(n) = A000217(A119042(n)). - _Tyler Busby_, Mar 27 2023

%t Rest[Select[FromDigits/@Tuples[{0,1,6},17],OddQ[Sqrt[8#+1]]&]] (* _Harvey P. Dale_, Jan 14 2017 *)

%Y Cf. A000217, A058418, A119042. See A119033 for a table of cross-references.

%K nonn,base

%O 1,2

%A _Giovanni Resta_, May 10 2006

%E a(23) from _Tyler Busby_, Mar 27 2023