Length of the maximal prefix of noncomposite numbers on row n of A249821.

Terms

a(0) =3a(1) =4a(2) =8a(3) =13a(4) =27a(5) =35a(6) =56a(7) =66a(8) =92a(9) =138a(10) =153a(11) =209a(12) =252a(13) =271a(14) =316a(15) =395a(16) =472a(17) =503a(18) =592a(19) =657a(20) =686a(21) =791a(22) =865a(23) =978a(24) =1140a(25) =1228a(26) =1269a(27) =1355a(28) =1396a(29) =1495