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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). 5

%I #24 Nov 17 2023 12:22:22

%S 2,3,5,7,13,31,37,79,113,179,181,199,353,727,787,907,937,967,983,1153,

%T 1193,1201,1409,1583,1597,1657,1831,1879,3083,3089,3319,3343,3391,

%U 3541,3643,3853,7057,7177,7507,7681,7867,7949,9103,9127,9173,9209,9439,9547,9601

%N 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 Original idea from _G. L. Honaker, Jr._.

%H T. D. Noe, <a href="/A054217/b054217.txt">Table of n, a(n) for n = 1..10000</a>

%e E.g., prime 113 has emirp 311 and 11311 is a palindromic prime, so 113 is a term.

%t 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 (Python)

%o from sympy import isprime

%o def ok(n):

%o if not isprime(n): return False

%o s = str(n); srev = s[::-1]

%o return isprime(int(srev)) and isprime(int(s[:-1] + srev))

%o print([k for k in range(10**4) if ok(k)]) # _Michael S. Branicky_, Nov 17 2023

%Y Cf. A054218, A000040, A006567, A048054, A002385.

%K nonn,base,nice

%O 1,1

%A _Patrick De Geest_, Feb 15 2000

%E Corrected (a(30)=3089 inserted) by _Harvey P. Dale_, Mar 26 2013

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Last modified April 23 16:40 EDT 2024. Contains 371916 sequences. (Running on oeis4.)