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A046254 a(1) = 4; a(n) is smallest number >= a(n-1) such that the juxtaposition a(1)a(2)...a(n) is a prime. 12
4, 7, 9, 9, 39, 47, 57, 81, 111, 123, 243, 283, 287, 313, 407, 507, 807, 1057, 1209, 1211, 1443, 1447, 1619, 2019, 2269, 2429, 2637, 2679, 2751, 3007, 3287, 3789, 3829, 3833, 3949, 4151, 4533, 4821, 5097, 5331, 5457, 5529, 5691, 6021, 6153, 6393, 6409 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..47.

MATHEMATICA

a[1] = 4; 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 ++ ]; k]; Table[ a[n], {n, 47}] (* Robert G. Wilson v, Aug 05 2005 *)

CROSSREFS

Cf. A069606, A074340, A033680, A033679, A033681, A046255, A046256, A046257, A046258, A046259, A111524.

Sequence in context: A200618 A085108 A106502 * A268227 A123573 A085746

Adjacent sequences:  A046251 A046252 A046253 * A046255 A046256 A046257

KEYWORD

nonn

AUTHOR

Patrick De Geest, May 15 1998

STATUS

approved

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Last modified August 15 18:38 EDT 2022. Contains 356148 sequences. (Running on oeis4.)