cp's OEIS Frontend

A054217 Primes p with property that p concatenated with its emirp p' (prime reversal) forms a palindromic prime of the form 'primemirp' (rightmost digit of p and leftmost digit of p' are blended together - p and p' palindromic allowed).

%I A054217 #24 Nov 17 2023 12:22:22
%S A054217 2,3,5,7,13,31,37,79,113,179,181,199,353,727,787,907,937,967,983,1153,
%T A054217 1193,1201,1409,1583,1597,1657,1831,1879,3083,3089,3319,3343,3391,
%U A054217 3541,3643,3853,7057,7177,7507,7681,7867,7949,9103,9127,9173,9209,9439,9547,9601
%N A054217 Primes p with property that p concatenated with its emirp p' (prime reversal) forms a palindromic prime of the form 'primemirp' (rightmost digit of p and leftmost digit of p' are blended together - p and p' palindromic allowed).
%C A054217 Original idea from _G. L. Honaker, Jr._.
%H A054217 T. D. Noe, <a href="/A054217/b054217.txt">Table of n, a(n) for n = 1..10000</a>
%e A054217 E.g., prime 113 has emirp 311 and 11311 is a palindromic prime, so 113 is a term.
%t A054217 empQ[n_]:=Module[{idn=IntegerDigits[n],rev},rev=Reverse[idn];And@@PrimeQ[ {FromDigits[ rev],FromDigits[Join[Most[idn],rev]]}]]; Select[Prime[ Range[ 1200]],empQ] (* _Harvey P. Dale_, Mar 26 2013 *)
%o A054217 (Python)
%o A054217 from sympy import isprime
%o A054217 def ok(n):
%o A054217     if not isprime(n): return False
%o A054217     s = str(n); srev = s[::-1]
%o A054217     return isprime(int(srev)) and isprime(int(s[:-1] + srev))
%o A054217 print([k for k in range(10**4) if ok(k)]) # _Michael S. Branicky_, Nov 17 2023
%Y A054217 Cf. A054218, A000040, A006567, A048054, A002385.
%K A054217 nonn,base,nice
%O A054217 1,1
%A A054217 _Patrick De Geest_, Feb 15 2000
%E A054217 Corrected (a(30)=3089 inserted) by _Harvey P. Dale_, Mar 26 2013