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 A292742 #14 Jul 24 2021 01:10:56 %S A292742 1,5,10393,45411263,31761301667,70697569679 %N A292742 Odd numbers k such that 2^psi(k) == phi(k) (mod k). %C A292742 a(7) > 5*10^11. - _Giovanni Resta_, Sep 23 2017 %e A292742 10393 = 19*547 is a term because 2^((19 + 1)*(547 + 1)) == (19 - 1)*(547 - 1) (mod 19*547). %o A292742 (PARI) a001615(n) = my(f=factor(n)); prod(i=1, #f~, f[i, 1]^f[i, 2] + f[i, 1]^(f[i, 2]-1)); %o A292742 isok(n) = n%2==1 && Mod(2, n)^a001615(n)==eulerphi(n); \\ after _Charles R Greathouse IV_ at A001615 %Y A292742 Cf. A000010, A001615, A292544. %K A292742 nonn,more %O A292742 1,2 %A A292742 _Altug Alkan_, Sep 22 2017 %E A292742 a(5)-a(6) from _Giovanni Resta_, Sep 23 2017