A320757 For p the n-th prime congruent to 1 (mod 4), a(n) is the clique number of the quadratic residue (Paley) graph over F_p, the field of order p.

2, 3, 3, 4, 4, 5, 5, 5, 5, 5, 6, 5, 6, 7, 7, 7, 7, 8, 7, 7, 8, 9, 7, 7, 7, 8, 8, 7, 8, 8, 9, 9, 9, 9, 8, 9, 9, 9, 9, 9, 11, 9, 11, 11, 9, 9, 11, 11, 9, 10, 11, 11, 12, 11, 11, 11, 11, 11, 11, 10, 10, 11

Offset: 1

Author

Jeremy F. Alm, Oct 20 2018

Keywords

• nonn
• more

Examples

			a(1) = 2, since the Paley graph of order 5 is a 5-cycle, and contains no triangle.
		

Links

• Eric Weisstein's World of Mathematics, Clique Number
• Eric Weisstein's World of Mathematics, Paley Graph

Crossrefs

Cf. A002144 (primes of form 4n + 1), A320837.