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

1,1

Links

Table of n, a(n) for n=1..47.

Mathematica

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

Prog

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

Crossrefs

Sequence in context: A179142 A039553 A135999 * A033268 A325903 A095643

Adjacent sequences: A162301 A162302 A162303 * A162305 A162306 A162307

Keyword

nonn,base

Author

Claudio Meller, Jun 30 2009

Status

approved