A051310 Euclid-Mullin sequence (A000945) with initial value a(1)=13 instead of a(1)=2.

13, 2, 3, 79, 6163, 7, 1601, 11, 137, 5, 199, 151, 263, 983, 31, 83, 30187890723499, 23847817657, 37, 67, 9661, 251, 73, 1214623152057970133, 24597089626521443731307390760915220105471840174452030562332559181845834101711082531

Offset: 1

Author

Labos Elemer

Keywords

• nonn

Links

• Robert Price, Table of n, a(n) for n = 1..36
• A. R. Booker, S. A. Irvine, The Euclid-Mullin graph, arXiv preprint arXiv:1508.03039 [math.NT], 2015-2016.

Crossrefs

Cf. A000945, A000946, A005265, A005266.

Programs

Mathematica

a[1]=13; a[n_] := First[ Flatten[ FactorInteger[ 1+Product[ a[ j ], {j, 1, n-1} ] ] ] ]; Array[a, 10]

PARI

spf(n)=factor(n)[1,1]
first(m)=my(v=vector(m)); v[1]=13; for(i=2, m, v[i]=spf(1+prod(j=1, i-1, v[j]))); v; \\ Anders Hellström, Aug 22 2015