A119103 Triangular numbers composed of digits {1,2,6}.
1, 6, 21, 66, 666, 2211, 6216, 212226, 222111, 1222266, 1261666, 16626261, 22121226, 22221111, 121111266, 126222216, 661261161, 2162616261, 2221211226, 2222211111, 21166222626, 66126661611, 166122226621, 216262612611, 222212111226, 222222111111, 22162261612611
Offset: 1
Links
- Giovanni Resta, Tridigital Triangular Numbers
Programs
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Mathematica
Flatten[Table[Select[FromDigits/@Tuples[{1,2,6},n],OddQ[Sqrt[8#+1]]&],{n,12}]] (* Harvey P. Dale, Mar 07 2015 *)
Formula
Extensions
a(24)-a(27) from Tyler Busby, Mar 14 2023