A033681 a(1) = 3; a(n) is smallest number >= a(n-1) such that the juxtaposition a(1)a(2)...a(n) is a prime.

3, 7, 9, 51, 51, 51, 97, 131, 157, 159, 243, 309, 327, 363, 383, 411, 487, 639, 873, 983, 1231, 1257, 1337, 1549, 1589, 2101, 2159, 2317, 2871, 2907, 4053, 4097, 4597, 4703, 5559, 5799, 6337, 6527, 6561, 6939, 7147, 7167, 7839, 8403, 8873, 9237, 9541, 9771

Offset

1,1

Links

Table of n, a(n) for n=1..48.

Mathematica

a[1] = 3; 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 *)

Crossrefs

Cf. A069605, A074339, A033680, A033679, A046254, A046255, A046256, A046257, A046258, A046259, A111524.

Sequence in context: A013624 A053366 A128052 * A074339 A355732 A115164

Adjacent sequences: A033678 A033679 A033680 * A033682 A033683 A033684

Keyword

nonn

Author

N. J. A. Sloane

Extensions

More terms from Patrick De Geest, May 15 1998

More terms from Robert G. Wilson v, Aug 05 2005

Status

approved