2*a(n) = m is the least even number m such that all sums m + prime(k), k=1..n are composite.

Terms

a(0) =1a(1) =3a(2) =11a(3) =44a(4) =44a(5) =56a(6) =56a(7) =101a(8) =101a(9) =101a(10) =359a(11) =359a(12) =359a(13) =664a(14) =664a(15) =821a(16) =821a(17) =821a(18) =866a(19) =866a(20) =866a(21) =2623a(22) =2623a(23) =2623a(24) =2623a(25) =2944a(26) =2944a(27) =2944a(28) =2944a(29) =2944