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

1,2

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

Table of n, a(n) for n=1..93.

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

Maple

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

Crossrefs

Cf. A056171, A076221.

Sequence in context: A065067 A086411 A105528 * A215776 A339085 A140887

Adjacent sequences: A076222 A076223 A076224 * A076226 A076227 A076228

Keyword

nonn

Author

Olivier Gérard

Status

approved