cp's OEIS Frontend

A289754 Primes of the form k!10 - 1, where k!10 is the decuple factorial number (A288327).

%I A289754 #10 Apr 14 2025 09:03:28
%S A289754 2,3,5,7,23,199,239999,7354367,719999999,2287853567,50399999999,
%T A289754 43193222037503,199094626418687,17254743876205585224626400657407,
%U A289754 620448401733239439359999999999999999999999999999,17999257015554062631539656405422901164857242675052543
%N A289754 Primes of the form k!10 - 1, where k!10 is the decuple factorial number (A288327).
%H A289754 Robert Price, <a href="/A289754/b289754.txt">Table of n, a(n) for n = 1..18</a>
%H A289754 Henri and Renaud Lifchitz, <a href="http://www.primenumbers.net/prptop/searchform.php?form=n10-1&amp;action=Search">PRP Records.Search for n!10-1</a>.
%H A289754 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 A289754 OpenPFGW Project, <a href="http://sourceforge.net/projects/openpfgw/">Primality Tester</a>.
%F A289754 a(n) = A288327(A204658(n)) - 1. - _Elmo R. Oliveira_, Apr 14 2025
%t A289754 MultiFactorial[n_, k_] := If[n<1, 1, n*MultiFactorial[n-k, k]];
%t A289754 Select[Table[MultiFactorial[i, 10] - 1, {i, 2, 100}], PrimeQ[#]&]
%Y A289754 Cf. A204658, A288327.
%K A289754 nonn
%O A289754 1,1
%A A289754 _Robert Price_, Jul 11 2017