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 A065822 #20 Jun 26 2024 03:03:43
%S A065822 323,377,22591,42619,49751,106711,119647,180947,2782057,2980823,
%T A065822 2981233,3794737,5112427,5285743,5732179,5964229,6073267,6669797,
%U A065822 6769927,7049407,8025547,8350633,8954023,9373213,10039471,10140517,10842901
%N A065822 Numbers k such that 5*phi(k) = 4*sigma(k).
%H A065822 Amiram Eldar, <a href="/A065822/b065822.txt">Table of n, a(n) for n = 1..335</a> (terms 1..60 from Harry J. Smith)
%t A065822 Select[Range[1085*10^4],5EulerPhi[#]==4DivisorSigma[1,#]&] (* _Harvey P. Dale_, Aug 11 2019 *)
%o A065822 (PARI) { n=0; for (m=1, 10^9, if (5*eulerphi(m) == 4*sigma(m), write("b065822.txt", n++, " ", m); if (n==60, return)) ) } \\ _Harry J. Smith_, Nov 01 2009
%o A065822 (PARI) is(n) = {my(f=factor(n)); 5*eulerphi(f) == 4*sigma(f);} \\ _Amiram Eldar_, Jun 26 2024
%Y A065822 Cf. A000010, A000203, A065818, A065819, A062699.
%K A065822 nonn
%O A065822 1,1
%A A065822 _Labos Elemer_, Nov 23 2001
%E A065822 a(9)-a(27) from _Harry J. Smith_, Nov 01 2009