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 A378315 #17 Jan 14 2025 13:34:21 %S A378315 1,15230439315,18887708385,74989937295,78103226565,86031400455, %T A378315 114958521405,179883837315,210096608085,367588711035,418094581905, %U A378315 461441147895,590648954805,649146021615,685787041485,836850895335,874197762165,990695282031,996070731201,1002913997085,1016370465201,1029306324501,1029869788311,1039854060045,1043905592457 %N A378315 Odd numbers k such that d(phi(k)) = phi(d(k)), where d=A000005 and phi=A000010. %C A378315 For n > 1, we have A001222(a(n)) >= 9. The smallest a(n) with A001222(a(n)) = 9 is a(65) = 1244586078645. %H A378315 Max Alekseyev, <a href="/A378315/b378315.txt">Table of n, a(n) for n = 1..65</a> %H A378315 Tong Lingling et al., <a href="https://mathoverflow.net/q/485625">Find the smallest odd integer n>1 such that phi(tau(n)) = tau(phi(n))</a>, MathOverflow, 2025. %H A378315 zhouzixiang2004, <a href="https://dmoj.ca/problem/dmopc21c10p5">DMOPC'21 Contest 10 P5 - Number Theory</a>, DMOJ Monthly Open Programming Competition, 2021. %Y A378315 Subsequence of A078148. %Y A378315 Cf. A000005, A000010, A033632. %K A378315 nonn %O A378315 1,2 %A A378315 _Max Alekseyev_, Jan 09 2025