314239934domain: NAppears in sequencesa(1)=1, then a(n)=2*a(n-1) if n is prime, a(n)=2*a(n-1)+1 if n not prime.at n=28A118255Numbers whose binary representation shows the distribution of prime numbers up to the n-th prime, using "0" for primes and "1" for nonprime numbers.at n=9A139104Bisection of A139104.at n=4A139112