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 A195685 #36 Nov 26 2021 14:48:05
%S A195685 17,43,47,71,101,107,109,151,197,223,317,349,461,521,569,631,673,701,
%T A195685 821,881,919,947,971,991,1051,1091,1109,1153,1181,1217,1231,1259,1321,
%U A195685 1361,1367,1549,1693,1801,1847,1933,1951,1979,2143,2207,2267,2297,2441,2801
%N A195685 Primes p for which tau(2p-1) = tau(2p+1) = 4.
%C A195685 Sequence terms are a subset of those listed in A086006 and A068497.
%C A195685 The numbers 2p-1, 2p, 2p+1 form a run (indeed, a maximal run) of three consecutive integers each with four positive divisors. The first two examples are 33, 34, 35 and 85, 86, 87. A039833 gives the first number in these maximal 3-integer runs. - _Timothy L. Tiffin_, Jul 05 2016
%H A195685 Charles R Greathouse IV, <a href="/A195685/b195685.txt">Table of n, a(n) for n = 1..10000</a>
%F A195685 a(n) = A248201(n)/2. - _Torlach Rush_, Jun 25 2021
%e A195685 tau(2*17-1) = tau(33) = tau(3*11) = 4 = tau(5*7) = tau(35) = tau(2*17+1) and tau(2*43-1) = tau(85) = tau(5*17) = 4 = tau(3*29) = tau(87) = tau(2*43+1). - _Timothy L. Tiffin_, Jul 05 2016
%p A195685 with(numtheory):
%p A195685 q:= p-> isprime(p) and tau(2*p-1)=4 and tau(2*p+1)=4:
%p A195685 select(q, [$1..3000])[]; # _Alois P. Heinz_, Apr 18 2019
%t A195685 Select[Prime[Range[500]], DivisorSigma[0, 2 # - 1] == DivisorSigma[0, 2 # + 1] == 4 &] (* _T. D. Noe_, Sep 22 2011 *)
%t A195685 Select[Mean[#]/2&/@SequencePosition[DivisorSigma[0,Range[6000]],{4,_,4}],PrimeQ] (* _Harvey P. Dale_, Nov 26 2021 *)
%o A195685 (PARI) lista(nn) = forprime(p=2, nn, if ((numdiv(2*p-1) == 4) && (numdiv(2*p+1) == 4), print1(p, ", "))); \\ _Michel Marcus_, Jul 06 2016
%Y A195685 Cf. A039833, A068497, A086006, A248201.
%K A195685 nonn
%O A195685 1,1
%A A195685 _Timothy L. Tiffin_, Sep 22 2011