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 A078769 #6 Jul 15 2025 08:27:21 %S A078769 2,3,4,6,8,10,12,14,18,20,24,30,36,42,48,60,84,90,120 %N A078769 Numbers k such that k * phi(k)^2 < sigma(k)^2. %e A078769 8*phi(8)^2=128, sigma(8)^2=225 and 128 < 225, hence 8 is a term of the sequence. %o A078769 (PARI) for (n=1,1000, if (eulerphi(n)^2*n<sigma(n)^2,print1(n","))) %Y A078769 Cf. A064375. %K A078769 nonn %O A078769 0,1 %A A078769 _Jon Perry_, Jan 09 2003 %E A078769 Name clarified by _Sean A. Irvine_, Jul 15 2025