cp's OEIS Frontend

A289861 Primes of the form k!10 - 2, where k!10 is the decuple factorial number (A288327).

%I A289861 #10 Feb 26 2025 06:35:38
%S A289861 2,3,5,7,37,73,229,1873,4957,7159,29599,293599,2953123,9476647,
%T A289861 1643049664639,30501459767616059381067752838134765623,
%U A289861 75901465778001946800870398616055887199,168354282831355577455162448188672669399,73004868196707960876168803928840928829809
%N A289861 Primes of the form k!10 - 2, where k!10 is the decuple factorial number (A288327).
%H A289861 Robert Price, <a href="/A289861/b289861.txt">Table of n, a(n) for n = 1..32</a>
%H A289861 Henri and Renaud Lifchitz, <a href="http://www.primenumbers.net/prptop/searchform.php?form=n10-2&amp;action=Search">PRP Records.Search for n!10-2</a>.
%H A289861 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 A289861 OpenPFGW Project, <a href="http://sourceforge.net/projects/openpfgw/">Primality Tester</a>.
%F A289861 a(n) = A288327(A283559(n)) - 2. - _Elmo R. Oliveira_, Feb 25 2025
%t A289861 MultiFactorial[n_, k_] := If[n<1, 1, n*MultiFactorial[n-k, k]];
%t A289861 Select[Table[MultiFactorial[i, 10] - 2, {i, 3, 100}], PrimeQ[#]&]
%t A289861 Select[Table[Times@@Range[n,1,-10]-2,{n,300}],PrimeQ] (* _Harvey P. Dale_, Sep 09 2021 *)
%Y A289861 Cf. A283559, A288327.
%K A289861 nonn
%O A289861 1,1
%A A289861 _Robert Price_, Jul 13 2017