a(1) = 3; a(n) = smallest number such that the forward as well as the reverse n-th partial concatenation is a prime for n>1. (Reverse concatenation is taken term-wise and not digit-wise).

A083993

a(1) = 3; a(n) = smallest number such that the forward as well as the reverse n-th partial concatenation is a prime for n>1. (Reverse concatenation is taken term-wise and not digit-wise).

Terms

    a(0) =3a(1) =1a(2) =1a(3) =39a(4) =87a(5) =57a(6) =171a(7) =129a(8) =219a(9) =399a(10) =459a(11) =1719a(12) =719a(13) =61a(14) =5811a(15) =383a(16) =1519a(17) =23889a(18) =1001a(19) =3133a(20) =4491a(21) =4767a(22) =519a(23) =4253a(24) =111a(25) =34251a(26) =12303a(27) =5143a(28) =16943a(29) =19293

External references