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 A152309 #13 Nov 23 2024 11:12:11 %S A152309 397,7867,10243,10333,12853,13789,14149,14293,14563,15643,17659,18379, %T A152309 18541,21277,21997,23059,23203,26731,27739,29179,29683,31771,34147, %U A152309 35461,35803,36541,37747,39979,40213,40429,41131,41491,44029,44101 %N A152309 Primes p such that the multiplicative order of 2 modulo p is (p-1)/9. %H A152309 Klaus Brockhaus, <a href="/A152309/b152309.txt">Table of n, a(n) for n=1..1000</a> %t A152309 okQ[p_] := MultiplicativeOrder[2, p] == (p-1)/9; %t A152309 Select[Prime[Range[10000]], okQ] (* _Jean-François Alcover_, Nov 23 2024 *) %o A152309 (Magma) [ p: p in PrimesUpTo(44101) | r eq 1 and Order(R!2) eq q where q,r is Quotrem(p,9) where R is ResidueClassRing(p) ]; %o A152309 (PARI) Vec(select(p->((p!=2) && (znorder(Mod(2, p)) == (p-1)/9)), primes(10000))) \\ _Michel Marcus_, Feb 09 2015 %Y A152309 Cf. A115591, A001133, A001134, A001135, A001136. %K A152309 nonn %O A152309 1,1 %A A152309 _Klaus Brockhaus_, Dec 02 2008