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

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

Crossrefs

Cf. A111525, A074346, A033680, A033679, A033681.

Cf. A046254, A046255, A046256, A046257, A046258, A046259.

Sequence in context: A018785 A176762 A001273 * A074346 A126973 A220045

Adjacent sequences: A111521 A111522 A111523 * A111525 A111526 A111527

Keyword

base,nonn

Author

Patrick De Geest, Zak Seidov and Robert G. Wilson v, Aug 05 2005

Status

approved