OFFSET
1,1
LINKS
Tyler Busby, Table of n, a(n) for n = 1..35
Andrew R. Booker and Sean A. Irvine, The Euclid-Mullin graph, arXiv preprint arXiv:1508.03039 [math.NT], 2015-2016.
MATHEMATICA
a[1]=47; a[n_] := First[ Flatten[ FactorInteger[ 1+Product[ a[ j ], {j, 1, n-1} ] ] ] ]; Array[a, 10]
PROG
(PARI) spf(n)=factor(n)[1, 1]; \\ A020639
first(m)=my(v=vector(m)); v[1]=47; for(i=2, m, v[i]=spf(1+prod(j=1, i-1, v[j]))); v \\ Anders Hellström, Nov 25 2015; corrected by Michel Marcus, Oct 10 2023
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved