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 A227070 #11 Jul 30 2013 14:56:12
%S A227070 1,2,3,5,6,9,11,17,21,26,33,41,51,65,81,101,126,129,161,201,251,257,
%T A227070 321,401,501,513,626,641,801,1001,1025,1251,1281,1601,2001,2049,2501,
%U A227070 2561,3126,3201,4001,4097,5001,5121,6251,6401,8001,8193,10001
%N A227070 Powers n such that the set s(n) = {k > 0 such that k^n ends with k} does not occur for smaller n.
%C A227070 These numbers might be called automorphic powers because the sets s(n) are called automorphic numbers. It appears that all numbers of the form 1 + 5^i are here. In fact, these appear to produce the only even numbers here. The set s(4) equals s(2). The set s(7) equals s(3). The set s(9) does not differ from s(5) until k = 10443. The set s(17) does not differ from s(9) until k = 108307. The sequence also has 126, 201, 251, 501, and 626, but there may be missing numbers.
%C A227070 Entries a(17)-a(49) have been tentatively obtained by comparing the terms < 10^30 in the sets s(n), for 2 <= n <= 10001. - _Giovanni Resta_, Jul 30 2013
%F A227070 Conjecture: a(n+1) = A003592(n) + 1. - _Eric M. Schmidt_, Jul 30 2013
%t A227070 ts = {}; t = {}; Do[s = Select[Range[11000000], PowerMod[#, n, 10^IntegerLength[#]] == # &]; If[! MemberQ[ts, s], Print[n]; AppendTo[ts, s]; AppendTo[t, n]], {n, 2, 101}]; t = Join[{1}, t]
%Y A227070 Cf. A003226 (n=2), A033819 (n=3), A068407 (n=5), A068408 (n=6).
%Y A227070 Cf. A072496 (n=11), A072495 (n=21), A076650 (n=26).
%Y A227070 Cf. A227071.
%K A227070 nonn,hard,more,base
%O A227070 1,2
%A A227070 _T. D. Noe_, Jul 29 2013
%E A227070 a(17)-a(49) from _Giovanni Resta_, Jul 30 2013