A046259 a(1) = 9; a(n) is smallest number >= a(n-1) such that the juxtaposition a(1)a(2)...a(n) is a prime.

9, 11, 21, 21, 23, 33, 37, 93, 119, 129, 133, 147, 293, 321, 429, 433, 497, 627, 661, 897, 1161, 1187, 1197, 1711, 1769, 1807, 2097, 2099, 4143, 4149, 4197, 4587, 4587, 5629, 5711, 5889, 6153, 6351, 6399, 6511, 6651, 7179, 7563, 7661, 8071, 8163, 9663

Offset: 1

Author

Patrick De Geest, May 15 1998

Keywords

• nonn

Crossrefs

Cf. A069611, A074345, A033680, A033679, A033681, A046254, A046255, A046256, A046257, A046258, A111524.

Programs

Mathematica

a[1] = 9; a[n_] := a[n] = Block[{k = a[n - 1], c = IntegerDigits @ Table[ a[i], {i, n - 1}]}, While[ !PrimeQ[ FromDigits @ Flatten @ Append[c, IntegerDigits[k]]], k += 2]; k]; Table[ a[n], {n, 48}] (* Robert G. Wilson v, Aug 05 2005 *)