A103856 Smallest prime factor of prime(n)! - prime(n)# + 1.

1, 1, 7, 4831, 3673, 16349, 5240507, 4159, 83, 3911, 401, 61, 66935021479, 199, 73, 152249, 379, 5014363, 181, 191, 277, 155893, 35851, 431, 1499

Offset: 1

Author

Reinhard Zumkeller, Feb 20 2005

Keywords

• nonn

Comments

a(26) has 160 digits and is too large to be included here.

Links

• Amiram Eldar, Table of n, a(n) for n = 1..26
• Reinhard Zumkeller, p(n)! - p(n)# + 1.

Crossrefs

Cf. A020639, A103855, A103857, A103891.

Programs

PARI

a(n) = if(n>2, factor(prime(n)!-factorback(primes(n))+1)[1, 1], 1); \\ Jinyuan Wang, Dec 30 2024

Formula

a(n) = A020639(A103855(n)).