a(n) = maximal length of partitions of n into distinct primes or -1 if there is no such partition.

Terms

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