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 A267487 #13 Apr 25 2017 10:02:32
%S A267487 2,3,7,31,127,1093,3511,8191,131071,524287
%N A267487 Primes p such that A001221(p+1)^(p-1) == 1 (mod p^2).
%C A267487 No further terms up to 10^9.
%C A267487 Are all terms of A000668 and A001220 in the sequence?
%C A267487 Does the sequence contain any terms not in A000668 or A001220 other than 2?
%p A267487 isA267487 := proc(p)
%p A267487 if isprime(p) then
%p A267487 A001221(p+1) ;
%p A267487 simplify(modp(% &^ (p-1),p^2) =1 );
%p A267487 else
%p A267487 false;
%p A267487 end if;
%p A267487 end proc:
%p A267487 p := 2;
%p A267487 for i from 1 do
%p A267487 if isA267487(p) then
%p A267487 printf("%d\n",p) ;
%p A267487 end if;
%p A267487 p := nextprime(p) ;
%p A267487 end do: # _R. J. Mathar_, Jan 23 2016
%t A267487 Select[Prime[Range[3200]], Mod[PrimeNu[# + 1], #^2]^(# - 1) == 1 &] (* _G. C. Greubel_, Apr 25 2017 *)
%o A267487 (PARI) forprime(p=1, 1e9, if(Mod(omega(p+1), p^2)^(p-1)==1, print1(p, ", ")))
%Y A267487 Cf. A000668, A001220, A260377.
%K A267487 nonn,more
%O A267487 1,1
%A A267487 _Felix Fröhlich_, Jan 15 2016