450344domain: NAppears in sequencesTetranacci sequence beginning with 3, 7, 12, 24.at n=18A356807a(n) is the number of positive integers k for which Sum_{i=1..r} p_i = Sum_{i=1..r} e_i = n, where p_1^e_1*...*p_r^e_r is the canonical prime factorization of k.at n=41A390784