A209189 Smallest prime factor of n^2 + n + 1.

7, 13, 3, 31, 43, 3, 73, 7, 3, 7, 157, 3, 211, 241, 3, 307, 7, 3, 421, 463, 3, 7, 601, 3, 19, 757, 3, 13, 7, 3, 7, 1123, 3, 13, 31, 3, 1483, 7, 3, 1723, 13, 3, 7, 19, 3, 37, 13, 3, 2551

Offset: 2

Author

N. J. A. Sloane, Mar 05 2012

Keywords

• nonn

Links

• PrimeFan, Listing of Esoteric Integer Sequences
• PrimeFan, Esoteric Integer Sequences [Cached copy]

Programs

Mathematica

Flatten[Table[SPF[n^2 + (n + 1)], {n, 2, 50}]]