A069611 a(1) = 9; a(n) = smallest number such that the juxtaposition a(1)a(2)...a(n) is a prime.

9, 7, 1, 9, 17, 13, 33, 23, 7, 77, 31, 59, 51, 27, 7, 269, 439, 11, 429, 163, 39, 11, 463, 77, 63, 39, 33, 93, 21, 139, 53, 159, 49, 9, 291, 111, 21, 23, 349, 83, 3, 37, 11, 57, 21, 219, 507, 1233, 429, 147, 627, 127, 399, 27, 63, 423, 111, 633, 1391, 297, 831, 283

Offset

1,1

Links

Table of n, a(n) for n=1..62.

Example

a(5) = 17 and the number 971917 is a prime.

Mathematica

a[1] = 9; a[n_] := a[n] = Block[{k = 1, c = IntegerDigits @ Table[ a[i], {i, n - 1}]}, While[ !PrimeQ[ FromDigits @ Flatten @ Append[c, IntegerDigits[k]]], k += 2]; k]; Table[ a[n], {n, 63}] (* Robert G. Wilson v, Aug 05 2005 *)

Crossrefs

Cf. A069602, A069604, A046259, A074345, A092528, A069603, A069605, A069606, A069607, A069608, A069609, A069610, A069611, A111525.

Sequence in context: A254249 A298752 A154396 * A083995 A195357 A328968

Adjacent sequences: A069608 A069609 A069610 * A069612 A069613 A069614

Keyword

nonn,base

Author

Amarnath Murthy, Mar 26 2002

Extensions

More terms from Jason Earls, Jun 13 2002

Status

approved