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%I #12 Jun 04 2017 13:30:09
%S 13,23,43,53,73,83,139,157,163,239,257,263,439,457,463,557,563,739,
%T 757,839,857,863,1297,1423,1447,1663,1861,1999,2111,2243,2273,2297,
%U 2423,2447,2663,2861,2969,2999,4111,4243,4273,4297,4423,4447,4663,4861,4969
%N n is prime and remains prime when its leading digit is replaced by each of 2, 4 and 8.
%C 2, 4 and 8 were chosen because they are powers of 2.
%H Harvey P. Dale, <a href="/A067227/b067227.txt">Table of n, a(n) for n = 1..1000</a>
%e 53 is prime and so are 23, 43, 83, so 53 is a term of the sequence.
%t (*replaces the leading digit of n by m*) f[n_, m_] := FromDigits[Flatten[Append[IntegerDigits[m], Drop[IntegerDigits[n], 1]]]]; Select[Range[10^4], PrimeQ[ # ] && PrimeQ[f[ #, 2]] && PrimeQ[f[ #, 4]] && PrimeQ[f[ #, 8]] & ]
%t Select[Prime[Range[700]],AllTrue[FromDigits/@Table[Join[{i},Rest[ IntegerDigits[ #]]],{i,{2,4,8}}],PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, Jun 04 2017 *)
%K base,nonn
%O 1,1
%A _Joseph L. Pe_, Feb 20 2002
%E Offset corrected to 1 and title simplified by _M. F. Hasler_, Nov 01 2014
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