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%I #29 Sep 17 2015 09:12:39
%S 11,31,53,101,110,131,149,159,169,189,223,231,243,249,283,297,301,310,
%T 311,313,327,331,361,381,397,429,437,453,463,503,513,530,533,561,627,
%U 641,651,657,691,779,813,861,937,941,951,961,973,1001,1010,1031,1049,1059,1069
%N Numbers n such that the concatenation A000461(d_1)//A000461(d_2)//...//A000461(d_k) is prime, where d_i is the i-th digit of n and n is k digits long.
%C If one of the digits is 0, it is read "zero zeros" and the term is thus omitted from the concatenation.
%C There are infinitely many numbers in this sequence. Any number can have an infinite number of 0's in its decimal expansion.
%e For n = 53, this becomes 5 fives and then 3 threes = 55555333. Since 55555333 is prime, 53 is a member of this sequence.
%o (Python)
%o import sympy
%o from sympy import isprime
%o def a():
%o ..for n in range(1,10**4):
%o ....num = ''
%o ....lst = list(str(n))
%o ....for i in lst:
%o ......num += i*int(i)
%o ....if isprime(int(num)):
%o ......print(n)
%o a()
%Y Cf. A000461.
%K nonn,base
%O 1,1
%A _Derek Orr_, Jun 01 2014
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