111100100100domain: NAppears in sequencesa(n) = A007088(A122232(n)).at n=3A122233a(n) = A007088(A122245(n)).at n=3A122246Deep factorization of n, written in binary: replace each factor p^e with the expression [primepi(p) [ e ]], iterate on these numbers, finally replace '[' and ']' with '1' and '0'.at n=4A300560