205731domain: NAppears in sequencesNumbers n such that n divides the (right) concatenation of all numbers <= n written in base 7 (most significant digit on right).at n=18A061936Numbers k such that 2*k^k - 1 is prime.at n=4A110931Number of Dyck paths of semilength n such that no level has more than six peaks.at n=12A287970