A162304 Triangular numbers that contain exactly 3 different decimal digits.

105, 120, 136, 153, 190, 210, 231, 253, 276, 325, 351, 378, 406, 435, 465, 496, 528, 561, 630, 703, 741, 780, 820, 861, 903, 946, 1081, 1128, 1176, 1225, 1431, 1770, 1891, 2080, 2278, 2556, 2628, 2775, 2926, 3321, 3403, 3655, 3828, 4005, 4465, 4656, 5253

Offset: 1

Author

Claudio Meller, Jun 30 2009

Keywords

• nonn
• base

Programs

Mathematica

Select[Accumulate[Range[150]],Count[DigitCount[#],0]==7&] (* Harvey P. Dale, Dec 02 2010 *)

PARI

isA162304(n)=issquare(n<<3+1)&#vecsort(Vec(Str(n)),,8)==3