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A214755 Primes formed by concatenating odd primes.

%I A214755 #19 Jun 06 2025 00:29:14
%S A214755 37,53,73,113,137,173,193,197,233,293,311,313,317,331,337,347,353,359,
%T A214755 367,373,379,383,389,397,433,523,541,547,557,571,577,593,613,617,673,
%U A214755 677,719,733,743,757,761,773,797,977,1013,1033,1093,1097,1117,1123,1129,1153
%N A214755 Primes formed by concatenating odd primes.
%C A214755 Subsequence of A019549.
%H A214755 David Radcliffe, <a href="/A214755/b214755.txt">Table of n, a(n) for n = 1..10000</a>
%o A214755 (Python)
%o A214755 from sympy import primerange
%o A214755 oddPrimes = list(primerange(3, 1154))
%o A214755 def tryPartitioning(binString):  # First digit is not 0
%o A214755     l = len(binString)
%o A214755     for t in range(1, l):
%o A214755         substr1 = binString[:t]
%o A214755         if (int(substr1) in oddPrimes) or (t>=2 and tryPartitioning(substr1)):
%o A214755             substr2 = binString[t:]
%o A214755             if substr2[0]!='0':
%o A214755                 if (int(substr2) in oddPrimes) or (l-t>=2 and tryPartitioning(substr2)):
%o A214755                     return 1
%o A214755     return 0
%o A214755 for p in oddPrimes:
%o A214755     if tryPartitioning(str(p)):
%o A214755         print(p, end=', ')
%Y A214755 Cf. A019549, A214754.
%K A214755 nonn,base
%O A214755 1,1
%A A214755 _Alex Ratushnyak_, Aug 03 2012