A076225 Counts of the maximum value in n-th row of A076221.

1, 2, 3, 2, 3, 2, 3, 3, 3, 2, 3, 3, 4, 3, 3, 3, 4, 4, 5, 5, 5, 4, 5, 5, 5, 4, 4, 4, 5, 5, 6, 6, 6, 5, 5, 5, 6, 5, 5, 5, 6, 6, 7, 7, 7, 6, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 7, 8, 8, 9, 8, 8, 8, 8, 8, 9, 9, 9, 9, 10, 10, 11, 10, 10, 10, 10, 10, 11, 11, 11, 10, 11, 11, 11, 10, 10, 10, 11, 11, 11, 11, 11

Offset: 1

Author

Olivier Gérard

Keywords

• nonn

Comments

Does a(n) always equal 1 + pi(n) - pi(n/2), where pi(x) is number of primes <= x? If so a(n) = A056171(n)+1. - Leroy Quet, Feb 06 2003.

This is true, because A076221(n,k) = n-1 iff either k = 1 or k is a prime with n/2 < k <= n. - Robert Israel, Aug 29 2016

Links

• Ethan Berkove and Michael Brilleslyper, Subgraphs of Coprime Graphs on Sets of Consecutive Integers, Integers (2022) Vol. 22, #A47, see p. 8.

Crossrefs

Cf. A056171, A076221.

Programs

Maple

seq(1+numtheory:-pi(n) - numtheory:-pi(floor(n/2)),n=1..100); # Robert Israel, Aug 29 2016