A051323 Euclid-Mullin sequence (A000945) with initial value a(1)=67 instead of a(1)=2.

67, 2, 3, 13, 5227, 7, 5, 4637, 107, 23, 1889, 50929, 31, 1677554191669, 538282187, 59, 37, 17046661, 81088366624779421, 11, 6242880316142699576539967984792911, 73, 17, 1187, 101, 883, 3491, 47, 83, 852851, 317, 1493, 579707, 109, 1579145715181, 179, 1618489, 331

Offset: 1

Author

Labos Elemer

Keywords

• nonn

Links

• Tyler Busby, Table of n, a(n) for n = 1..42

Crossrefs

Cf. A000945, A000946, A005265, A005266.

Programs

Mathematica

a[1]=67; a[n_] := First[ Flatten[ FactorInteger[ 1+Product[ a[ j ], {j, 1, n-1} ] ] ] ]; Array[a, 10]

PARI

spf(n)=my(f=factor(n)[1, 1]); f
first(m)=my(v=vector(m)); v[1]=67; for(i=2, m, v[i]=spf(1+prod(j=1, i-1, v[j]))); v \\ Anders Hellström, Dec 06 2015

Extensions

a(21)-a(38) from Robert Price, Jul 12 2015