A051325 Euclid-Mullin sequence (A000945) with initial value a(1)=73 instead of a(1)=2.

73, 2, 3, 439, 7, 5, 6729871, 103, 23, 92581, 13, 19, 2453563465139998636061911, 739, 3167, 47356379285063777, 463, 3673, 2918137, 41, 17, 2307841395358410336056217199460000033494100011180619106269258300884070797073446703818111

Offset: 1

Author

Labos Elemer

Keywords

• easy
• nonn

Links

• Robert Price, Table of n, a(n) for n = 1..44

Crossrefs

Cf. A000945, A000946, A005265, A005266.

Programs

Mathematica

a[1]=73; 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]=73; for(i=2, m, v[i]=spf(1+prod(j=1, i-1, v[j]))); v \\ Anders Hellström, Dec 06 2015