A257368 - OEIS

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A257368

Numbers n such that the decimal expansions of both n and n^2 have 2 as smallest digit and 8 as largest digit.

278, 528, 582, 826, 2385, 2585, 2868, 2872, 2875, 2878, 2885, 4782, 4832, 4872, 5278, 5328, 6872, 7238, 7258, 7268, 7582, 8232, 8266, 8275, 8278, 8284, 8522, 8524, 8528, 8628, 8732, 8822, 23385, 23628, 23782, 23826, 25582, 25668, 25785, 25856, 26238, 26878

(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 @@ Prepend[Take[d, -2], First@ d] == 0 && d[[2]] > 0 && d[[8]] > 0]; Select[Range@ 27000, fQ@ # && fQ[#^2] &] (* Michael De Vlieger, Apr 27 2015 *)

PROG

(PARI) is(n) = vecmin(digits(n))==2 && vecmin(digits(n^2))==2 && vecmax(digits(n))==8 && vecmax(digits(n^2))==8

CROSSREFS

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

Sequence in context: A264371 A154231 A252249 * A056995 A228135 A188446

Adjacent sequences: A257365 A257366 A257367 * A257369 A257370 A257371

KEYWORD

nonn,base

AUTHOR

Felix Fröhlich, Apr 25 2015

STATUS

approved