A066576 - OEIS

%I #12 Sep 08 2022 08:45:04

%S 30031,510511,9699691,223092871,6469693231,7420738134811,

%T 304250263527211,13082761331670031,614889782588491411,

%U 32589158477190044731,1922760350154212639071,117288381359406970983271

%N Composite Euclid numbers: numbers of the form p# + 1, where p# denotes the primorial of the prime p.

%C 30031 appears in Wells's "Curious and Interesting Numbers" as the smallest composite number of the form p# + 1.

%D David Wells, "The Penguin Dictionary of Curious and Interesting Numbers," Revised Edition, Penguin Books, London, England, 1997, page 166.

%H Amiram Eldar, <a href="/A066576/b066576.txt">Table of n, a(n) for n = 1..341</a>

%t Do[c = Product[ Prime[i], {i, 1, n}] + 1; If[ !PrimeQ[c], Print[c]], {n, 1, 20} ]

%o (Magma) [a: n in [2..19]| not IsPrime(a) where a is 1+&*[NthPrime(k):k in [1..n]]]; // _Marius A. Burtea_, Feb 18 2020

%Y Cf. A014545, A006862.

%K nonn

%O 1,1

%A _Joseph L. Pe_, Jan 07 2002

%E Edited by _Robert G. Wilson v_, Jan 09 2002