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 A333828 #14 Aug 31 2021 04:36:06 %S A333828 8,18,13,1,15,7,14,10,9,13,0,7,6,6,13,5,14,16,0,4,11,8,8,10,8,8,3,12, %T A333828 6,7,19,8,10,12,11,1,1,15,2,12,8,8,10,19,4,10,19,7,17,8,12,14,9,19,11, %U A333828 18,16,14,19,9,4,2,16,11,0,12,11,1,6,11,12,3,3,16,11 %N A333828 The 20-adic integer x = ...70D9AE7F1DI8 satisfying x^5 = x. %C A333828 Letters A through J represent the base-20 digits 10 through 19, respectively. %C A333828 Conjecture: There exists a nontrivial n-adic integer x satisfying x^5 = x, and x^2, x^3, and x^4 are not x, if and only if n has a prime factor of the form 4k+1. Further, there is one nontrivial pair (x and -x) for each different prime factor of the form 4k+1. %H A333828 Patrick A. Thomas, <a href="/A333828/a333828_1.txt">Solutions to x^5=x up to base 100</a> %F A333828 The last n+1 digits of 8^(5^n) in base 20, for all n. %e A333828 8^25 in base 20 ends in the digits 13, 18, 8 (or ...DI8 in extended hexadecimal notation). %Y A333828 Cf. A120817, A210850, A331548. %K A333828 nonn,base %O A333828 0,1 %A A333828 _Patrick A. Thomas_, Apr 07 2020