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 A332635 #31 Apr 23 2020 22:39:49
%S A332635 1,2,3,1,4,9,3,4,2,12,10,15,40,34,9,11,3,28,50,55,15,24,31,80,8,16,86,
%T A332635 65,54,40,71,54,62,85,122,114,1,40,4,87,45,126,172,53,93,109,139,28,
%U A332635 167,78,19,222,182,136,230,231,110,163,264,45,92,134,177,241
%N A332635 a(n) = n!! mod prime(n).
%C A332635 a(n) > 0, as n!! cannot be divisible by prime(n): n < prime(n) for all n, so the prime factorization of n!! never includes prime(n).
%C A332635 a(n) = 1 for n = 1, 4, 37, 2721, ... .
%C A332635 a(n) = n for n = 1, 2, 3, 86, 122, ... .
%H A332635 Andrew Nelson, <a href="/A332635/b332635.txt">Table of n, a(n) for n = 1..5000</a>
%F A332635 a(n) = n!! mod prime(n), where n!! denotes the double factorial of n.
%e A332635 For n = 4, a(4) = 4!! mod prime(4) = 8 mod 7 = 1.
%t A332635 Table[Mod[n!!, Prime[n]], {n, 100}]
%o A332635 (PARI) a(n) = my(p=prime(n)); lift(prod(i=0, (n-1)\2, Mod(n-2*i, p))); \\ _Michel Marcus_, Feb 25 2020
%Y A332635 Cf. A000040 (primes), A006882 (double factorials), A091858 (n! mod prime(n)).
%K A332635 nonn,easy
%O A332635 1,2
%A A332635 _Andrew Nelson_, Feb 17 2020