1,2

Eggleton et al. show that k is in this sequence if and only if A277515(k)=3.

R. B. Eggleton, J. S. Kimberley and J. A. MacDougall, Square-free rank of integers, submitted.

Jason Kimberley, Table of n, a(n) for n = 1..10000

a(n) = floor(n*sqrt(6)/2).

a(n) = A000196(A032528(n)).

a(5)=6 because the quotient of 3*5^2 by 2 is 37 which lies between 6^2 and 7^2.

(MAGMA) [Isqrt(3*n^2 div 2): n in [1..60]];

Complement of A277645.

Sequence in context: A039258 A187968 A176253 * A039199 A172269 A115180

Adjacent sequences: A277641 A277642 A277643 * A277645 A277646 A277647

nonn,easy

Jason Kimberley, Oct 26 2016

approved