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 A254074 Numbers k such that the decimal expansions of both k and k^2 have 5 as the digit with the smallest value and 9 as the digit with the largest value. 3
 759576, 97759786, 97957576, 887579686, 987759576, 987859786, 7599859786, 7679576587, 8756697886, 8766958976, 9775989867, 9897756766, 9978965766, 76797588887, 88766997576, 97978858887, 99777685676, 99789658666, 99879856766, 767897685676, 869866586666 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The first digit of a term is either 7, 8 or 9 and the last digit is either 5, 6 or 7. Conjecture: no term is a multiple of 5. - Chai Wah Wu, Sep 10 2017 LINKS Chai Wah Wu, Table of n, a(n) for n = 1..1224 (n = 1..326 from Hiroaki Yamanouchi). MATHEMATICA fQ[n_] := Block[{c = DigitCount@ n}, And[Plus @@ Take[c, {1, 4}] == 0, Last@ c == 0, c[[5]] > 0, c[[9]] > 0]]; Select[Range@ 10000000, fQ@ # && fQ[#^2] &] (* Michael De Vlieger, May 05 2015 *) PROG (PARI) is(n) = vecmin(digits(n))==5 && vecmin(digits(n^2))==5 && vecmax(digits(n))==9 && vecmax(digits(n^2))==9 CROSSREFS Cf. A137147, A256630, A256631, A256633, A256634, A256708, A256709, A256889, A257197, A257210, A257211, A256601, A257310, A249915, A257123, A257368, A257485, A257486, A257498, A238553, A257534, A254071. Sequence in context: A306959 A137468 A183825 * A014889 A014888 A234990 Adjacent sequences: A254071 A254072 A254073 * A254075 A254076 A254077 KEYWORD nonn,base AUTHOR Felix Fröhlich, May 03 2015 EXTENSIONS a(14)-a(21) from Hiroaki Yamanouchi, May 07 2015 STATUS approved

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Last modified August 4 01:40 EDT 2024. Contains 374905 sequences. (Running on oeis4.)