Difference between n and the next prime greater than n.

Terms

a(0) =2a(1) =1a(2) =1a(3) =2a(4) =1a(5) =2a(6) =1a(7) =4a(8) =3a(9) =2a(10) =1a(11) =2a(12) =1a(13) =4a(14) =3a(15) =2a(16) =1a(17) =2a(18) =1a(19) =4a(20) =3a(21) =2a(22) =1a(23) =6a(24) =5a(25) =4a(26) =3a(27) =2a(28) =1a(29) =2