257972domain: NAppears in sequencesNumber of Carlitz compositions of n with exactly three descents.at n=18A241693Solution of the complementary equation a(n) = a(n-1) + a(n-2) + b(n), where a(0) = 1, a(1) = 3, b(0) = 2, b(1) = 4, b(2) = 5, and (a(n)) and (b(n)) are increasing complementary sequences.at n=22A295862