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 A289856 #10 Apr 15 2025 08:27:22
%S A289856 10139,2026769,13749310319,213458046676619,191898783962510369,
%T A289856 157952079428395476360490147277859119,
%U A289856 29215606371473169285018060091249259296619,2395415678676082004163677716234578672981800778515369
%N A289856 Primes of the form k!2 - 256, where k!2 is the double factorial number (A006882).
%H A289856 Robert Price, <a href="/A289856/b289856.txt">Table of n, a(n) for n = 1..12</a>
%H A289856 Henri and Renaud Lifchitz, <a href="http://www.primenumbers.net/prptop/searchform.php?form=n2-256&action=Search">PRP Records.Search for n!2-256</a>.
%H A289856 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 A289856 OpenPFGW Project, <a href="http://sourceforge.net/projects/openpfgw/">Primality Tester</a>.
%F A289856 a(n) = A006882(A265114(n)) - 256. - _Elmo R. Oliveira_, Apr 14 2025
%t A289856 MultiFactorial[n_, k_] := If[n<1, 1, n*MultiFactorial[n-k, k]];
%t A289856 Select[Table[MultiFactorial[i, 2] - 256, {i, 8, 100}], PrimeQ[#]&]
%Y A289856 Cf. A006882, A265114.
%K A289856 nonn
%O A289856 1,1
%A A289856 _Robert Price_, Jul 13 2017