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 A175507 Numbers such that each digit from 0 to 9 appears at least 7 times in the digits of their divisors. 1
 7980, 8190, 9360, 10920, 11760, 11880, 12870, 13230, 13860, 14820, 15960, 16380, 16740, 17640, 17940, 18216, 18270, 18360, 18720, 18810, 18900, 19040, 19080, 19140, 19656, 19740, 20196, 20580, 20790, 20880, 21168, 21560, 21840, 22176 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..1000 Erich Friedman, What's Special About This Number? (See entry 7980.) EXAMPLE 5460 is not in the sequence because the divisors, 1, 2, 3, 4, 5, 6, 7, 10, 12, 13, 14, 15, 20, 21, 26, 28, 30, 35, 39, 42, 52, 60, 65, 70, 78, 84, 91, 105, 130, 140, 156, 182, 195, 210, 260, 273, 364, 390, 420, 455, 546, 780, 910, 1092, 1365, 1820, 2730, 5460, contain the digit 7 only 6 times (namely once in 7, 70, 78, 273, 780 and 2730), which is not enough. MATHEMATICA fQ[n_] := Block[{s = Transpose@ Tally[ Sort[ Flatten[ IntegerDigits@# & /@ Divisors@ n]]]}, First@ s == {0, 1, 2, 3, 4, 5, 6, 7, 8, 9} && Min@ Last@ s > 6]; k = 1; lst = {}; While[k < 22319, If[ fQ@k, AppendTo[lst, k]]; k++ ]; lst (* Robert G. Wilson v, Jul 31 2010 *) CROSSREFS Cf. A059436. Sequence in context: A236786 A252190 A233730 * A126893 A217068 A043614 Adjacent sequences: A175504 A175505 A175506 * A175508 A175509 A175510 KEYWORD base,nonn,easy AUTHOR R. J. Mathar, Jun 02 2010 EXTENSIONS More terms from Robert G. Wilson v, Jul 31 2010 STATUS approved

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Last modified September 16 00:43 EDT 2024. Contains 375959 sequences. (Running on oeis4.)