where
is the least prime factor. The first few terms
are 2, 3, 7, 43, 13, 53, 5, 6221671, 38709183810571, 139, ... (OEIS A000945),
with 51 terms known as of Oct. 5, 2026. The 52nd term is the least
prime factor of the 335-digit composite number.
Guy, R. K. and Nowakowski, R. "Discovering Primes with Euclid." Delta (Waukesha)5, 49-63, 1975.Mullin,
A. A. "Recursive Function Theory." Bull. Amer. Math. Soc.69,
737, 1963.Naur, T. "Mullin's Sequence of Primes Is Not Monotonic."
Proc. Amer. Math. Soc.90, 43-44, 1984.Sloane, N. J. A.
Sequence A000945/M0863 in "The On-Line
Encyclopedia of Integer Sequences."Wagstaff, S. S. "Computing
Euclid's Primes." Bull. Institute Combin. Applications8, 23-32,
1993.
and
is the least prime factor. The first few terms
are 2, 3, 7, 43, 13, 53, 5, 6221671, 38709183810571, 139, ... (OEIS A000945),
with 51 terms known as of Oct. 5, 2026. The 52nd term is the least
prime factor of the 335-digit composite number 
.
