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 A108510 #4 Mar 30 2012 17:37:43 %S A108510 1979,2699,7649,1131569,2482199,2886839,90425537,2774476799 %N A108510 Primes p such that 3^A000027*(7*p) is a subsequence of A033631. %C A108510 There is no further term up to prime(300000000). %e A108510 Let n be a natural number and m=3^n*7*90425537; %e A108510 then sigma(phi(m)) = sigma(3^(n-1)*2*6*90425536) = sigma(3^n*2^8*677*2087) = sigma(3^n)*8*90425538 = sigma(3^n)*sigma(7)*sigma(90425537) = sigma(3^n*7*90425537) = sigma(m), %e A108510 hence m is in A033631 and the prime number 90425537 is a term of this sequence. %Y A108510 Cf. A000027, A033631. %K A108510 more,nonn %O A108510 1,1 %A A108510 _Farideh Firoozbakht_, Jun 07 2005