1,2

R. H. Hardin, Table of n, a(n) for n = 1..210

Empirical: a(n) = a(n-1) + a(n-6) - a(n-7).

Empirical for n mod 6 = 0: a(n) = (2/3)*n

Empirical for n mod 6 = 1: a(n) = (2/3)*n + (1/3)

Empirical for n mod 6 = 2: a(n) = (2/3)*n + (2/3)

Empirical for n mod 6 = 3: a(n) = (2/3)*n + 1

Empirical for n mod 6 = 4: a(n) = (2/3)*n + (1/3)

Empirical for n mod 6 = 5: a(n) = (2/3)*n + (2/3).

Empirical g.f.: x*(1 + x + x^2 + x^4) / ((1 - x)^2*(1 + x)*(1 - x + x^2)*(1 + x + x^2)). - Colin Barker, Dec 20 2018

All solutions for n=4:

..2....4....3

Row 1 of A257062.

Sequence in context: A057365 A014245 A096386 * A273663 A135671 A079420

Adjacent sequences: A257060 A257061 A257062 * A257064 A257065 A257066

nonn

R. H. Hardin, Apr 15 2015

approved