A256708 Numbers n such that the decimal expansions of both n and n^2 have 0 as smallest digit and 8 as largest digit.

280, 508, 780, 805, 1028, 1078, 1280, 1308, 1680, 1780, 1805, 1840, 2078, 2608, 2680, 2780, 2800, 2801, 2802, 2805, 2840, 2850, 3280, 3580, 3780, 3805, 3808, 3850, 4048, 4078, 4280, 4780, 4804, 4805, 4880, 5008, 5018, 5028, 5048, 5078, 5080, 5084, 5180, 5280

Offset: 1

Author

Felix Fröhlich, Apr 08 2015

Keywords

• nonn
• base

Links

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

Crossrefs

Cf. A136814, A136820, A136825, A136829, A136832, A136840, A136845, A136849, A136904, A256630, A256631, A256633, A256634, A256709.

Programs

Mathematica

fQ[n_] := Block[{c = DigitCount@ n}, And[c[[9]] == 0, c[[8]] > 0, c[[10]] > 0]]; Select[Range@ 5280, fQ@ # && fQ[#^2] &] (* Michael De Vlieger, Apr 12 2015 *)
maxdQ[n_]:=Module[{id1=IntegerDigits[n],id2=IntegerDigits[n^2]},Max[ id1] == Max[ id2] == 8&&Min[id1]==Min[id2]==0]; Select[Range[6000],maxdQ] (* Harvey P. Dale, Oct 19 2021 *)

PARI

is(n) = vecmin(digits(n))==0 && vecmin(digits(n^2))==0 && vecmax(digits(n))==8 && vecmax(digits(n^2))==8