Triangular numbers composed of digits {1,2,9}.
A119109
Triangular numbers composed of digits {1,2,9}.
Terms
- a(0) =1a(1) =21a(2) =91a(3) =2211a(4) =222111a(5) =22221111a(6) =229119121a(7) =291212911a(8) =2222211111a(9) =222222111111a(10) =299992122991
External references
- oeis: A119109