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A162304 Triangular numbers that contain exactly 3 different decimal digits. 7
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified June 22 04:06 EDT 2021. Contains 345367 sequences. (Running on oeis4.)