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 A154555 #5 May 26 2024 01:25:25
%S A154555 7,11,19,43,47,127,131,163,179,191,199,263,347,367,419,431,443,491,
%T A154555 503,523,571,619,691,727,743,787,839,863,1051,1087,1091,1123,1291,
%U A154555 1319,1367,1451,1487,1499,1571,1579,1583,1667,1723,1783,1823,1931,1951,2003,2039
%N A154555 Primes p such that m=(p-1)/2 is the least number such that p divides m!+1.
%C A154555 The graph of A073944 shows two prominent curves. This sequence gives the primes on the lower curve. Primes on the upper curve are in sequence A154554.
%H A154555 T. D. Noe, <a href="/A154555/b154555.txt">Table of n, a(n) for n=1..1000</a>
%t A154555 Rest[Reap[Do[p=Prime[i]; f=1; m=1; While[f=Mod[f*m,p]; f+1<p, m++ ]; If[m==(p-1)/2, Sow[p]], {i,400}]]][[1,1]]
%Y A154555 Cf. A073944, A154554.
%K A154555 nonn
%O A154555 1,1
%A A154555 _T. D. Noe_, Jan 12 2009