A257123 - OEIS

A257123

Numbers n such that the decimal expansions of both n and n^2 have 2 as smallest digit and 7 as largest digit.

%I #15 May 02 2015 10:20:04

%S 275,2574,2725,2765,4762,5725,6762,7244,7262,23765,25744,27244,27325,

%T 27434,27465,27525,27632,27665,47725,52275,52376,52475,52576,52675,

%U 57242,67426,72266,72275,72424,72426,72576,72624,73325,73725,74326,75725,233725,233744

%N Numbers n such that the decimal expansions of both n and n^2 have 2 as smallest digit and 7 as largest digit.

%H Felix Fröhlich, <a href="/A257123/b257123.txt">Table of n, a(n) for n = 1..1000</a>

%o (PARI) is(n) = vecmin(digits(n))==2 && vecmin(digits(n^2))==2 && vecmax(digits(n))==7 && vecmax(digits(n^2))==7

%Y Cf. A137094, A256630, A256631, A256633, A256634, A256708, A256709, A256889, A257197, A257210, A257211, A256601, A257310, A249915, A257368, A257485, A257486, A257498, A257534.

%K nonn,base

%O 1,1

%A _Felix Fröhlich_, Apr 25 2015