A111524 - OEIS

A111524

a(1) = 10; a(n) is smallest number >= a(n-1) such that the juxtaposition a(1)a(2)...a(n) is a prime.

10, 13, 23, 49, 111, 113, 171, 211, 293, 309, 309, 469, 639, 759, 951, 1037, 1057, 1083, 1257, 1269, 1287, 1341, 1551, 1637, 1677, 1981, 1989, 2021, 2059, 2357, 2583, 2697, 2967, 3289, 6789, 7073, 7323, 7369, 7463, 7501, 7709, 7869, 8029, 8069, 8077, 8519

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OFFSET

1,1

LINKS

Michael S. Branicky, Table of n, a(n) for n = 1..449

MATHEMATICA

a[1] = 10; a[n_] := a[n] = Block[{k = a[n - 1] + 1 + Mod[a[n - 1], 2], c = IntegerDigits @ Table[ a[i], {i, n - 1}]}, While[ !PrimeQ[ FromDigits @ Flatten @ Append[c, IntegerDigits[k]]], k += 2]; k]; Table[ a[n], {n, 46}] (* Robert G. Wilson v, Aug 05 2005 *)

PROG

(Python)

from sympy import isprime

def aupton(terms):

alst, astr = [10], "10"

while len(alst) < terms:

k = alst[-1] + (1 - alst[-1]%2)

while not isprime(int(astr+str(k))): k += 2

alst.append(k)

astr += str(k)

return alst

print(aupton(46)) # Michael S. Branicky, Oct 13 2021