A051328 Euclid-Mullin sequence (A000945) with initial value a(1)=89 instead of a(1)=2.

89, 2, 179, 3, 61, 13, 53, 5, 20086919971, 14911308271, 6016479583547124128827234315771, 9697, 23, 31, 17, 4229, 7937, 22739, 7043, 11, 163, 19, 41, 227399, 73, 4441, 1907, 7, 2647566144823, 47, 337, 211, 1171, 404489, 676721, 71, 653, 4703, 29, 587, 199, 37537, 167, 6893009

Offset: 1

Author

Labos Elemer

Keywords

• easy
• nonn

Crossrefs

Cf. A000945, A000946, A005265, A005266.

Programs

Mathematica

a[1]=89; 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]=89; for(i=2, m, v[i]=spf(1+prod(j=1, i-1, v[j]))); v \\ Anders Hellström, Dec 06 2015

Extensions

a(35)-a(44) from Robert Price, Jul 09 2015