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Numbers that divide primorial numbers plus one (p#+1).
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%I #6 Mar 25 2017 23:42:54

%S 2,3,7,19,31,59,61,73,97,131,139,149,167,173,181,211,223,271,277,307,

%T 313,317,331,347,463,467,509,571,601,673,809,827,877,881,953,983,997,

%U 1031,1033,1039,1051,1063,1069,1109,1259,1279,1283,1291,1297,1361,1381

%N Numbers that divide primorial numbers plus one (p#+1).

%C The smallest composite member of the sequence is 1843 (19 * 97), which divides 17#+1 (19 * 97 * 277). Based on Euclid's proof that there are infinitely many primes.

%H Jeppe Stig Nielsen, <a href="/A113165/b113165.txt">Table of n, a(n) for n = 1..1000</a>

%e 59 is in the sequence because 13#+1 = 30031 = 59 * 509.

%o (PARI) n=0;for(i=2,1e5,p=Mod(1,i);forprime(q=2,factor(i)[1,1],if(p==-1,print(n++," ",i);break());p*=q)) \\ _Jeppe Stig Nielsen_, Mar 25 2017

%Y Cf. A002110 (primorials), A018239 (primorial primes), A000945 (Euclid-Mullin sequence), A006862 (primorials plus one).

%K easy,nonn

%O 1,1

%A _Franklin T. Adams-Watters_, Jan 05 2006