A257485 - OEIS

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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.

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

Felix Fröhlich, Table of n, a(n) for n = 1..10000

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

Cf. A256630, A256631, A256633, A256634, A256708, A256709, A256889, A257197, A257210, A257211, A256601, A257310, A249915, A257123, A257368.

Sequence in context: A116989 A152503 A099688 * A255106 A253039 A237229

Adjacent sequences: A257482 A257483 A257484 * A257486 A257487 A257488

KEYWORD

nonn,base

AUTHOR

Felix Fröhlich, Apr 26 2015

STATUS

approved