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Least nontrivial exponent e > 2 such that n^2 is a substring of n^e (n >= 0).
1

%I #9 Mar 21 2018 04:34:54

%S 3,3,6,6,7,3,7,6,22,11,3,13,26,54,123,27,27,40,100,43,6,43,54,42,12,3,

%T 37,43,9,37,6,19,102,102,43,96,83,45,67,34,12,128,168,102,182,44,152,

%U 104,184,52,3,17,35,75,164,67,127,22,134,98,7,124,117,146,77,146,156,87

%N Least nontrivial exponent e > 2 such that n^2 is a substring of n^e (n >= 0).

%H Robert Israel, <a href="/A175394/b175394.txt">Table of n, a(n) for n = 0..2000</a>

%e a(2)=6 because 2^2=4 is a substring of 2^6=64

%e a(4)=7 because 4^2=16 is a substring of 4^7=16384.

%p f:= proc(n) local pat,e;

%p pat:= sprintf("%d",n^2);

%p for e from 3 do if StringTools:-Search(pat, sprintf("%d",n^e))<> 0 then return e fi od:

%p end proc:

%p map(f, [$0..100]); # _Robert Israel_, Mar 20 2018

%t lne[n_]:=Module[{e=3,idn2=IntegerDigits[n^2]},While[!MemberQ[ Partition[ IntegerDigits[n^e], Length[ idn2],1],idn2],e++];e]; Array[lne,70,0] (* _Harvey P. Dale_, Aug 17 2013 *)

%Y Cf. A008856, A033819, A045537, A074250.

%K base,nonn

%O 0,1

%A _Zak Seidov_, Apr 29 2010