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 A338130 #16 Feb 13 2022 10:36:52
%S A338130 1,4,7,10,19,28,37,46,55,64,73,82,109,136,163,190,217,244,271,298,325,
%T A338130 352,379,406,433,460,487,514,541,568,595,622,649,676,703,730,811,892,
%U A338130 973,1054,1135,1216,1297,1378,1459,1540,1621,1702,1783,1864,1945,2026
%N A338130 Positive numbers k such that the ternary representation of k^k ends with that of k.
%C A338130 All terms are of the form 3*m + 1 for some m >= 0.
%C A338130 The first differences appear to contain only powers of 3 and to be weakly increasing.
%C A338130 Run lengths in first differences appear to be regular and suggest a simple procedure to generate the sequence.
%H A338130 Rémy Sigrist, <a href="/A338130/b338130.txt">Table of n, a(n) for n = 1..10000</a>
%H A338130 Rémy Sigrist, <a href="/A338130/a338130.png">Ternary plot of the terms < 3^10</a> (blue squares correspond to 1's and red squares to 2's)
%H A338130 <a href="/index/Ar#automorphic">Index entries for sequences related to automorphic numbers</a>
%e A338130 The ternary representation of 4^4 ("100111") ends with that of 4 ("11"), so 4 is a term.
%t A338130 Select[Range[2100],Take[IntegerDigits[#^#,3],-IntegerLength[#,3]] == IntegerDigits[ #,3]&] (* _Harvey P. Dale_, Feb 13 2022 *)
%o A338130 (PARI) is(n, base=3) = Mod(n, base^#digits(n, base))^n==n
%Y A338130 Cf. A082576, A338128, A338129.
%K A338130 nonn,base
%O A338130 1,2
%A A338130 _Rémy Sigrist_, Oct 11 2020