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 A129517 #23 Jan 29 2022 10:26:10
%S A129517 11,19,23,31,43,67,71,131,151,163,167,179,223,227,239,271,311,347,359,
%T A129517 419,439,443,463,487,491,523,563,571,619,647,683,691,719,739,751,787,
%U A129517 911,919,947,967,983,1019,1031,1039,1051,1063,1091,1103,1123,1187,1223
%N A129517 Odd primes p such that p divides (p-1)!!-1.
%C A129517 All terms are primes of the form 4k+3 (A002145). A002145 is the union of {a(n)} and A129518 (numbers k > 2 such that k divides (k-2)!!-1 and (k-3)!!-1).
%C A129517 Primes such that ((p-1)/2)! = (-1)^((p^2-1)/8) in the finite field F_p of p elements. For example, 11 is a term since ((11-1)/2)! = 5! = -1 = (-1)^((121-1)/8) in F_11. - _Luis H. Gallardo_, Dec 30 2021
%H A129517 Jon E. Schoenfield, <a href="/A129517/b129517.txt">Table of n, a(n) for n = 1..10000</a>
%t A129517 Select[Prime@Range[2,200],Mod[(#-1)!!-1,#]==0&] (* _Giorgos Kalogeropoulos_, Jan 09 2022 *)
%Y A129517 Cf. A006882, A002145, A129518, A129516.
%K A129517 nonn
%O A129517 1,1
%A A129517 _Alexander Adamchuk_, Apr 18 2007