A074346 - OEIS

%I #14 Oct 15 2021 11:29:25

%S 10,13,23,49,111,113,171,211,293,309,333,387,463,479,513,687,933,973,

%T 993,1329,1433,1449,1551,2071,2271,2423,2587,2621,2659,2757,2771,2911,

%U 3081,3243,3279,3671,4243,4247,4371,4453,4511,5229,6097,6177,6293,6571

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

%H Michael S. Branicky, <a href="/A074346/b074346.txt">Table of n, a(n) for n = 1..439</a>

%t 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 *)

%o (Python)

%o from sympy import isprime

%o def aupton(terms):

%o     alst, astr = [10], "10"

%o     while len(alst) < terms:

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

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

%o         alst.append(k)

%o         astr += str(k)

%o     return alst

%o print(aupton(46)) # _Michael S. Branicky_, Oct 13 2021

%Y Cf. A111524, A111525, A074336.

%Y Cf. A074338, A074339, A074340, A074341, A074342, A074343, A074344, A074345.

%K nonn,base

%O 1,1

%A _Zak Seidov_, Sep 23 2002

%E More terms from _Robert G. Wilson v_, Aug 05 2005