cp's OEIS Frontend

A289851 Primes of the form k!2 - 8, where k!2 is the double factorial number (A006882).

%I A289851 #12 Apr 14 2025 12:27:18
%S A289851 7,97,937,654729067,13113070457687988603440617,
%T A289851 563862029680583509947946867,
%U A289851 536347102817482913555411512425352545980058003572241486357421867,352999527454840466971061863960307904899505075341088595453568994140617
%N A289851 Primes of the form k!2 - 8, where k!2 is the double factorial number (A006882).
%H A289851 Robert Price, <a href="/A289851/b289851.txt">Table of n, a(n) for n = 1..10</a>
%H A289851 Henri and Renaud Lifchitz, <a href="http://www.primenumbers.net/prptop/searchform.php?form=n2-8&amp;action=Search">PRP Records.Search for n!2-8</a>.
%H A289851 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 A289851 OpenPFGW Project, <a href="http://sourceforge.net/projects/openpfgw/">Primality Tester</a>.
%F A289851 a(n) = A006882(A259359(n)) - 8. - _Elmo R. Oliveira_, Apr 14 2025
%t A289851 MultiFactorial[n_, k_] := If[n<1, 1, n*MultiFactorial[n-k, k]];
%t A289851 Select[Table[MultiFactorial[i, 2] - 8, {i, 5, 100}], PrimeQ[#]&]
%t A289851 Select[Range[5,100]!!-8,PrimeQ] (* _Harvey P. Dale_, Feb 06 2024 *)
%Y A289851 Cf. A006882, A259359.
%K A289851 nonn
%O A289851 1,1
%A A289851 _Robert Price_, Jul 13 2017
%E A289851 Definition corrected by _Harvey P. Dale_, Feb 06 2024