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

1,1

Links

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

Mathematica

fQ[n_] := Block[{c = DigitCount@ n}, And[c[[9]] == 0, c[[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 *)

Prog

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

Crossrefs

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

Sequence in context: A241803 A361038 A245208 * A207075 A242039 A234911

Adjacent sequences: A256705 A256706 A256707 * A256709 A256710 A256711

Keyword

nonn,base

Author

Felix Fröhlich, Apr 08 2015

Status

approved