a(1) = 1; for n>1, a(n) = least k such that concatenation of n copies of k with all previous concatenations gives a prime.

A111471

a(1) = 1; for n>1, a(n) = least k such that concatenation of n copies of k with all previous concatenations gives a prime.

Terms

    a(0) =1a(1) =9a(2) =7a(3) =3a(4) =29a(5) =19a(6) =21a(7) =121a(8) =7a(9) =211a(10) =207a(11) =11a(12) =221a(13) =347a(14) =99a(15) =123a(16) =303a(17) =189a(18) =1131a(19) =1179a(20) =2069a(21) =3437a(22) =2211a(23) =211a(24) =3169a(25) =1551a(26) =3493a(27) =7433a(28) =6939a(29) =1053

External references