a(1)=1, a(n)=2a(n-1)+1 if a(n-1) is prime, a(n)=a(n-1)+1 otherwise.

Terms

a(0) =1a(1) =2a(2) =5a(3) =11a(4) =23a(5) =47a(6) =95a(7) =96a(8) =97a(9) =195a(10) =196a(11) =197a(12) =395a(13) =396a(14) =397a(15) =795a(16) =796a(17) =797a(18) =1595a(19) =1596a(20) =1597a(21) =3195a(22) =3196a(23) =3197a(24) =3198a(25) =3199a(26) =3200a(27) =3201a(28) =3202a(29) =3203