This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A090516 #13 Sep 03 2018 02:50:21
%S A090516 1,4,8,9,16,25,27,32,36,49,64,81,121,125,128,169,196,216,243,256,289,
%T A090516 324,343,361,484,512,529,576,625,676,729,784,841,961,1024,1089,1296,
%U A090516 1369,1521,1681,1728,1764,1849,1936,2025,2048,2187,2197,2304,2401,2601
%N A090516 Perfect powers (at least a square) in which neighboring digits are distinct.
%C A090516 Sequence must be infinite but a proof is needed. Subsidiary sequences; Perfect squares or perfect cubes etc. in which neighboring digits are distinct.
%C A090516 On the other hand, for k >= 22 we might expect only finitely many k-th powers where neighboring digits are distinct (see A318763). - _Robert Israel_, Sep 03 2018
%H A090516 Robert Israel, <a href="/A090516/b090516.txt">Table of n, a(n) for n = 1..10000</a>
%p A090516 N:= 5000:
%p A090516 filter:= proc(n) local L;
%p A090516 L:= convert(n,base,10);
%p A090516 not member(0, L[2..-1]-L[1..-2])
%p A090516 end proc:
%p A090516 P:= sort(convert({seq(seq(i^k,i=1..floor(N^(1/k))),k=2..ilog2(N))},list)):
%p A090516 select(filter, P); # _Robert Israel_, Sep 03 2018
%Y A090516 Cf. A001597 (perfect powers), A075309 (distinct-digit perfect powers), A318763.
%K A090516 base,easy,nonn
%O A090516 1,2
%A A090516 _Amarnath Murthy_, Dec 06 2003
%E A090516 Corrected and extended by _Rick L. Shepherd_, Jul 01 2005
%E A090516 Offset corrected by _Robert Israel_, Sep 03 2018