A051320 Euclid-Mullin sequence (A000945) with initial value a(1)=53 instead of a(1)=2.

53, 2, 107, 3, 7, 11, 2620003, 707431, 1993, 4409, 131, 17, 5, 858127, 79, 163, 19, 46061, 31, 17707, 157, 43, 3135504913004354085487249, 9893869, 149, 1001472037, 16979051, 387853, 61, 13, 227, 41, 206779, 443, 37, 1709

Offset: 1

Author

Labos Elemer

Keywords

• easy
• nonn

Links

• Robert Price, Table of n, a(n) for n = 1..48

Crossrefs

Cf. A000945, A000946, A005265, A005266.

Programs

Mathematica

a[1]=53; a[n_] := First[ Flatten[ FactorInteger[ 1+Product[ a[ j ], {j, n-1} ] ] ] ]; Array[a, 15]

PARI

spf(n)=my(f=factor(n)[1, 1]); f
first(m)=my(v=vector(m)); v[1]=53; for(i=2, m, v[i]=spf(1+prod(j=1, i-1, v[j]))); v \\ Anders Hellström, Nov 26 2015