265142domain: NAppears in sequencesNumber of rational points of Klein curve over GF(2^n).at n=17A048635Number of length 1+3 0..n arrays with no four consecutive terms having the sum of any three elements equal to three times the fourth.at n=21A249291a(n) = Sum_{k=1..n} (k/gcd(n, k))^3.at n=34A343513