cp's OEIS Frontend

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.

A369105 Primes p such that p+2 has only prime factors congruent to -1 modulo 4.

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%I A369105 #15 Jun 03 2024 03:48:32
%S A369105 5,7,17,19,29,31,41,47,61,67,79,97,101,127,131,137,139,149,197,199,
%T A369105 211,229,241,251,269,277,281,307,359,379,397,421,439,461,467,487,499,
%U A369105 521,569,571,587,601,617,619,631,641,647,691,709,719,727,751,757,787,809,811
%N A369105 Primes p such that p+2 has only prime factors congruent to -1 modulo 4.
%C A369105 Jones and Zvonkin call these primes BCC primes, where BCC stands for Bujalance, Cirre, and Conder.
%H A369105 Amiram Eldar, <a href="/A369105/b369105.txt">Table of n, a(n) for n = 1..10000</a>
%H A369105 E. Bujalance, F. J. Cirre, and M. D. E. Conder, <a href="https://doi.org/10.1112/jlms.12296">Bounds on the orders of groups of automorphisms of a pseudo-real surface of given genus</a>, Journal of the London Mathematical Society, Volume 101, Issue 2, p. 877-906, (2019).
%H A369105 Gareth A. Jones and Alexander K. Zvonkin, <a href="https://arxiv.org/abs/2401.00270">A number-theoretic problem concerning pseudo-real Riemann surfaces</a>, arXiv:2401.00270 [math.NT], 2023. See page 1.
%t A369105 Select[Prime[Range[150]], PrimeQ[f=First/@FactorInteger[#+2]] == Table[True,{j,PrimeNu[#+2]}] && Mod[f,4] == Table[3, {m,PrimeNu[#+2]}] &]
%o A369105 (PARI) is1(n) = {my(p = factor(n)[, 1]); for(i = 1, #p, if(p[i] % 4 == 1, return(0))); 1;};
%o A369105 lista(pmax) = forprime(p = 3, pmax, if(is1(p+2), print1(p, ", "))); \\ _Amiram Eldar_, Jun 03 2024
%Y A369105 Cf. A001221, A004614, A004767, A027748, A369107, A369108, A369109, A369111.
%K A369105 nonn
%O A369105 1,1
%A A369105 _Stefano Spezia_, Jan 13 2024