a(1) = 4 and then least composite such that every partial concatenation of 2 or more terms is a prime.

A086474

a(1) = 4 and then least composite such that every partial concatenation of 2 or more terms is a prime.

Terms

    a(0) =4a(1) =21a(2) =39a(3) =49a(4) =93a(5) =99a(6) =143a(7) =183a(8) =207a(9) =231a(10) =247a(11) =261a(12) =267a(13) =531a(14) =533a(15) =549a(16) =889a(17) =999a(18) =1167a(19) =1641a(20) =1701a(21) =1809a(22) =2019a(23) =2327a(24) =2349a(25) =2469a(26) =2553a(27) =3043a(28) =3093a(29) =3123

External references