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 A194257 #38 Mar 09 2024 12:20:42
%S A194257 127,1093,19531,5229043,25646167,917087137,52379047267,153436090543,
%T A194257 502628805631,11016462577051,18871143464293,251059142817757,
%U A194257 1812169199976451,1940350890330343
%N A194257 Primes of the form p^6 + p^5 + p^4 + p^3 + p^2 + p + 1 when p is prime.
%C A194257 These primes are generated by exactly A163268.
%C A194257 This sequence is included in A088550.
%C A194257 These numbers are repunit primes 1111111_n, so they are Brazilian primes and are terms of A085104.
%C A194257 Subsequence of A088550. - _Hartmut F. W. Hoft_, May 05 2017
%H A194257 Robert Israel, <a href="/A194257/b194257.txt">Table of n, a(n) for n = 1..10000</a>
%F A194257 a(n) = A193574(A163268(n)^6). - _Hartmut F. W. Hoft_, May 08 2017
%p A194257 select(isprime, map(p -> add(p^i,i=0..6), select(isprime, [2,seq(i,i=3..1000,2)]))); # _Robert Israel_, May 05 2017
%t A194257 a194257[n_] := Select[Map[(Prime[#]^7-1)/(Prime[#]-1)&, Range[n]], PrimeQ]
%t A194257 a194257[70] (* data *) (* _Hartmut F. W. Hoft_, May 05 2017 *)
%t A194257 Select[Table[Total[p^Range[0,6]],{p,Prime[Range[100]]}],PrimeQ] (* _Harvey P. Dale_, Mar 09 2024 *)
%Y A194257 Cf. A085104, A088550, A100330, A163268.
%K A194257 nonn
%O A194257 1,1
%A A194257 _Bernard Schott_, Dec 21 2012