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 A289821 #4 Jul 13 2017 21:27:21
%S A289821 151,2504901671,664565853951271,3091650738175271,26582634158079271,
%T A289821 126757680265215271,142299187144047333874073599271,
%U A289821 546216992715109618958387336810111087297326406997164406744285183999999999271
%N A289821 Primes of the form k!3-729, where k!3 is the triple factorial number (A007661).
%H A289821 Robert Price, <a href="/A289821/b289821.txt">Table of n, a(n) for n = 1..13</a>
%H A289821 Henri & Renaud Lifchitz, <a href="http://www.primenumbers.net/prptop/searchform.php?form=n3-729&action=Search">PRP Records.Search for n!3-729.</a>
%H A289821 Joe McLean, <a href="http://web.archive.org/web/20091027034731/http://uk.geocities.com/nassarawa%40btinternet.com/probprim2.htm">Interesting Sources of Probable Primes</a>
%H A289821 OpenPFGW Project, <a href="http://sourceforge.net/projects/openpfgw/">Primality Tester</a>
%t A289821 MultiFactorial[n_, k_] := If[n<1, 1, n*MultiFactorial[n-k, k]];
%t A289821 Select[Table[MultiFactorial[i, 3] - 729, {i, 11, 100}], PrimeQ[#]&]
%Y A289821 Cf. A247466.
%K A289821 nonn
%O A289821 1,1
%A A289821 _Robert Price_, Jul 12 2017