262818domain: NAppears in sequencesNumber of (n+4) X 8 0..1 matrices with each 5 X 5 subblock idempotent.at n=23A224686Number of eleven-prime Carmichael numbers less than 10^n.at n=5A299711a(n) = Sum_{d|n} phi(n/d) * (2^d - 1).at n=17A346558