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okQ[n_]:=Module[{idn=IntegerDigits[n], p13, p31}, p13=FromDigits[ Join[ idn, {1, 3}]]; p31=FromDigits[Join[idn, {3, 1}]]; PrimeQ[p13]&&NextPrime[p13] == p31]; Select[Prime[Range[16000]], okQ] (* From _Harvey P. Dale, _, Jan 21 2012 *)
editing
approved
19, 853, 2287, 2467, 4243, 4513, 4621, 5431, 5701, 7243, 7477, 7591, 7927, 8221, 8317, 9283, 9439, 9817, 10039, 12781, 13933, 14461, 14923, 15727, 16693, 17443, 18199, 18217, 19207, 20749, 21139, 22147, 23761, 25471, 26701, 26953, 27481, 28111, 28447, 28579
Harvey P. Dale, <a href="/A176601/b176601.txt">Table of n, a(n) for n = 1..2000</a>
okQ[n_]:=Module[{idn=IntegerDigits[n], p13, p31}, p13=FromDigits[ Join[ idn, {1, 3}]]; p31=FromDigits[Join[idn, {3, 1}]]; PrimeQ[p13]&&NextPrime[p13] == p31]; Select[Prime[Range[16000]], okQ] (* From Harvey P. Dale, Jan 21 2012 *)
More terms from Harvey P. Dale, Jan 21 2012
approved
editing
Primes p that p//13 and p//31 are consecutive primes.
19, 853, 2287, 2467, 4243, 4513, 4621, 5431, 5701, 7243, 7477, 7591, 7927, 8221, 8317, 9283, 9439, 9817, 10039, 12781
1,1
See A176600
19//13 = 1913 = prime(293), 19//31 = 1931 = prime(294), 19 = prime(8) is 1st term
853//13 = 85313 = prime(8306), 853//31 = 85331 = prime(8307), 853 = prime(147) is 2nd term
base,nonn
Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), Apr 21 2010
approved