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 A058341 #19 Mar 09 2025 05:12:26 %S A058341 3,5,7,13,17,19,37,41,43,61,73,89,97,101,109,113,157,163,181,193,233, %T A058341 241,257,277,281,313,337,349,353,397,401,409,421,433,449,457,461,487, %U A058341 521,541,577,593,601,613,617,641,661,673,701,733,757,761,769,821,829 %N A058341 Primes p such that phi(x) = p - 1 has more than 2 solutions. %C A058341 There are always at least 2 such values: p and 2p. - _Franklin T. Adams-Watters_, May 17 2010 %H A058341 Amiram Eldar, <a href="/A058341/b058341.txt">Table of n, a(n) for n = 1..10000</a> %H A058341 Max Alekseyev, <a href="https://oeis.org/wiki/User:Max_Alekseyev/gpscripts">PARI/GP Scripts for Miscellaneous Math Problems</a> (invphi.gp). %e A058341 3 is a term since phi(x) = 3 - 1 = 2 has more than 2 solutions: 3, 4 and 6. %e A058341 5 is a term since phi(x) = 5 - 1 = 4 has more than 2 solutions: 5, 8, 10 and 12. %o A058341 (PARI) isok(p) = isprime(p) && #invphi(p-1) > 2; \\ _Amiram Eldar_, Mar 08 2025, using _Max Alekseyev_'s invphi.gp (see links). %Y A058341 Cf. A000010, A006093. %Y A058341 Cf. A014197, A058277, A005277. - _Franklin T. Adams-Watters_, May 17 2010 %K A058341 nonn %O A058341 1,1 %A A058341 _Labos Elemer_, Dec 14 2000