22221111
domain: N
Appears in sequences
- Triangular numbers that contain exactly 2 different digits.at n=32A062691
- Triangular numbers in which neighboring digits differ at most by 1. Allowed neighbors of 9 are 0, 8 and 9.at n=29A068149
- Triangular numbers whose representation is made of nontrivial runs of identical digits.at n=7A116055
- Triangular numbers composed of digits {0,1,2}.at n=11A119033
- Triangular numbers composed of digits {1,2,3}.at n=11A119097
- Triangular numbers composed of digits {1,2,4}.at n=6A119099
- Triangular numbers composed of digits {1,2,5}.at n=16A119101
- Triangular numbers composed of digits {1,2,6}.at n=13A119103
- Triangular numbers composed of digits {1,2,7}.at n=9A119105
- Triangular numbers composed of digits {1,2,8}.at n=13A119107
- Triangular numbers composed of digits {1,2,9}.at n=5A119109
- Triangular numbers having only 1 or 2 different digits in base 10.at n=39A213516
- Triangular numbers obtained as the concatenation of 2*k and k.at n=9A226742
- Triangular numbers of the form 2..21..1; n_times 2 followed with n_times 1; n >= 1.at n=3A319170