A256709 - OEIS

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A256709

Numbers n such that the decimal expansions of both n and n^2 have 0 as smallest digit and 9 as largest digit.

509, 890, 903, 905, 930, 950, 960, 970, 980, 990, 1039, 1091, 1095, 1097, 1390, 1709, 1903, 1905, 1930, 1970, 1980, 1990, 2049, 2093, 2095, 2097, 2190, 2509, 2809, 2903, 2905, 2907, 2930, 2970, 2990, 3009, 3049, 3079, 3090, 3092, 3095, 3097, 3098, 3099, 3209

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OFFSET

1,1

LINKS

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

MATHEMATICA

fQ[n_] := Block[{c = DigitCount@ n}, And[c[[9]] > 0, c[[10]] > 0]]; Select[Range@ 3209, fQ@ # && fQ[#^2] &] (* Michael De Vlieger, Apr 12 2015 *)

PROG

(PARI) is(n) = vecmin(digits(n))==0 && vecmin(digits(n^2))==0 && vecmax(digits(n))==9 && vecmax(digits(n^2))==9

CROSSREFS

Cf. A136836, A256630, A256631, A256633, A256634, A256708.

Sequence in context: A198195 A142819 A183058 * A110025 A059763 A031421

Adjacent sequences: A256706 A256707 A256708 * A256710 A256711 A256712

KEYWORD

nonn,base

AUTHOR

Felix Fröhlich, Apr 08 2015

STATUS

approved