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A257485 Numbers n such that the decimal expansions of both n and n^2 have 2 as smallest digit and 9 as largest digit. 9
927, 962, 982, 2293, 2393, 2593, 2693, 2792, 2923, 2927, 2932, 2937, 2964, 2973, 2977, 2982, 2983, 4792, 4923, 4927, 5692, 6292, 6923, 6925, 6927, 7923, 7924, 7927, 8792, 8925, 9232, 9233, 9267, 9268, 9273, 9286, 9287, 9288, 9325, 9326, 9327, 9342, 9423, 9427 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
MATHEMATICA
fQ[n_] := Block[{d = DigitCount@ n}, Plus @@ Join[First@ d, Last@ d] == 0 && d[[2]] > 0 && d[[9]] > 0]; Select[Range@ 10000, fQ@ # && fQ[#^2] &] (* Michael De Vlieger, Apr 27 2015 *)
s2l9Q[n_]:=Max[IntegerDigits[n]]==9&&Min[IntegerDigits[n]]==2; Select[ Range[ 10000], AllTrue[{#, #^2}, s2l9Q]&] (* Harvey P. Dale, Dec 06 2018 *)
PROG
(PARI) is(n) = vecmin(digits(n))==2 && vecmin(digits(n^2))==2 && vecmax(digits(n))==9 && vecmax(digits(n^2))==9
CROSSREFS
Sequence in context: A116989 A152503 A099688 * A255106 A253039 A237229
KEYWORD
nonn,base
AUTHOR
Felix Fröhlich, Apr 26 2015
STATUS
approved

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Last modified June 24 19:44 EDT 2024. Contains 373690 sequences. (Running on oeis4.)