A257197 Numbers k such that the decimal expansions of both k and k^2 have 1 as smallest digit and 6 as largest digit.

116, 146, 1116, 1146, 1156, 1246, 1465, 1556, 1616, 3516, 3621, 4611, 4621, 4631, 11116, 11146, 11156, 11465, 11556, 11642, 15216, 16231, 21556, 22631, 25146, 25162, 25621, 33516, 34156, 35116, 35146, 35162, 36211, 36215, 36512, 46111, 46112, 46211, 46331

Offset: 1

Author

Felix Fröhlich, Apr 18 2015

Keywords

• base
• nonn

Links

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

Crossrefs

Cf. A256630, A256631, A256633, A256634, A256708, A256709, A256889, A257210, A257211.

Programs

Mathematica

sd1Q[n_]:=Module[{idn=IntegerDigits[n]},Min[idn]==1&&Max[idn]==6]; Select[ Range[50000],AllTrue[{#,#^2},sd1Q]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Nov 22 2020 *)

PARI

is(n) = vecmin(digits(n))==1 && vecmin(digits(n^2))==1 && vecmax(digits(n))==6 && vecmax(digits(n^2))==6

Extensions

Corrected b-file from Felix Fröhlich, Mar 18 2022