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 A066074 #15 Jan 05 2018 02:56:27
%S A066074 11,17,23,23,41,31,59,41,71,47,53,47,59,89,83,71,71,97,71,79,89,167,
%T A066074 103,83,113,139,167,223,107,131,179,233,167,127,251,191,151,239,181,
%U A066074 179,359,167,223,311,251,239,269,191,167,179,227,233,191,239,191,293
%N A066074 Primes arising in A066073.
%H A066074 Harry J. Smith, <a href="/A066074/b066074.txt">Table of n, a(n) for n = 1..1000</a>
%e A066074 p=71 appears in the sequence at 9th, 16th, 17th and 19th positions as -1+sigma(x) for x=30, 46, 51, 55.
%t A066074 Do[s=-1+DivisorSigma[1, n]; If[PrimeQ[s]&&!PrimeQ[n], Print[s]], {n, 1, 256}]
%o A066074 (PARI) { n=0; for (m=1, 10^9, if (!isprime(m) && isprime(p=sigma(m) - 1), write("b066074.txt", n++, " ",p); if (n==1000, return)) ) } \\ _Harry J. Smith_, Nov 10 2009
%o A066074 (PARI) lista(nn) = forcomposite(n=1, nn, if (isprime(p=(sigma(n)-1)), print1(p, ", "))); \\ _Michel Marcus_, Jan 05 2018
%Y A066074 Cf. A000203, A058340, A066071, A066072, A066073, A066074, A066075, A066076, A066077, A066080.
%K A066074 nonn
%O A066074 1,1
%A A066074 _Labos Elemer_, Dec 03 2001