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 A030986 #25 Feb 16 2025 08:32:35 %S A030986 5,75,875,6875,96875,296875,4296875,4296875,404296875,9404296875, %T A030986 39404296875,639404296875,6639404296875,86639404296875,86639404296875, %U A030986 2086639404296875,52086639404296875 %N A030986 3-automorphic numbers ending in 5: final digits of 3*n^2 agree with n. %C A030986 a(n) is the unique positive integer less than 10^n such that a(n) is divisible by 5^n and 3*a(n) - 1 is divisible by 2^n. - _Eric M. Schmidt_, Aug 18 2012 %H A030986 Eric M. Schmidt, <a href="/A030986/b030986.txt">Table of n, a(n) for n = 1..1000</a> %H A030986 <a href="/index/Ar#automorphic">Index entries for sequences related to automorphic numbers</a> %H A030986 <a href="/index/Fi#final">Index entries for sequences related to final digits of numbers</a> %H A030986 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/AutomorphicNumber.html">Automorphic Number</a> %o A030986 (Sage) [crt(inverse_mod(3, 2^n), 0, 2^n, 5^n) for n in range(1, 1001)] # _Eric M. Schmidt_, Aug 18 2012 %K A030986 nonn,base %O A030986 1,1 %A A030986 _Eric W. Weisstein_