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 A242960 #12 Jan 24 2020 07:00:31 %S A242960 4,5,10,20,40,80,491531,983062,1966124,2457655,3932248,4915310, %T A242960 6389903,9339089,9830620,12288275,12779806,18678178,19169709,19661240, %U A242960 24576550,25559612,28017267,31949515,37356356,38339418,39322480,46695445,49153100,51119224,56034534 %N A242960 Numbers n such that 7^A000010(n) == 1 (mod n^2). %H A242960 Giovanni Resta, <a href="/A242960/b242960.txt">Table of n, a(n) for n = 1..425</a> %o A242960 (PARI) for(n=2, 10^9, if(Mod(7, n^2)^(eulerphi(n))==1, print1(n, ", "))) %Y A242960 Cf. A077816, A242959, A000010. All primes in this sequence are in A123693. %K A242960 nonn %O A242960 1,1 %A A242960 _Felix Fröhlich_, May 27 2014 %E A242960 Terms a(23) and beyond from _Giovanni Resta_, Jan 24 2020