Hi SeqFans, You will find A000040 scrolling here : http://www.echolaliste.com/echoprimes-b.htm or http://www.echolalie.org/gbnums/echoprimes-b.htm Neil : any worth to include it as a comment to A000040 in the OEIS ? Regards, Jacques. PS - A000040 is the sequence (2,3,5,7,11,13,17,....)