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%I #10 Dec 27 2024 15:31:59
%S 2,13,19,31,37,43,61,73,79,97,127,139,151,157,163,181,193,211,283,331,
%T 349,367,379,409,421,457,463,487,499,541,547,577,601,619,643,661,673,
%U 709,727,739,757,787,811,829,853,877,883,919,991,997,1039,1063,1069
%N n is prime and remains prime when its leading digit is increased by one.
%H Harvey P. Dale, <a href="/A067208/b067208.txt">Table of n, a(n) for n = 1..1000</a>
%e Increasing the leading digit of 97 (prime) by one yields 107 (prime). Hence 97 is a term of the sequence.
%t f[n_] := Block[{a = IntegerDigits[n] }, a[[1]] = a[[1]] + 1; Return[ FromDigits[a]]]; Select[ Range[1100], PrimeQ[ # ] && PrimeQ[ f[ # ]] & ]
%t Select[Prime[Range[200]],PrimeQ[FromDigits[Join[{IntegerDigits[#][[1]]+1},Rest[IntegerDigits[#]]]]]&] (* or *) Select[Prime[ Range[ 200]],PrimeQ[#+10^(IntegerLength[#]-1)]&] (* _Harvey P. Dale_, Dec 27 2024 *)
%K base,easy,nonn
%O 1,1
%A _Joseph L. Pe_, Feb 19 2002
%E Edited and extended by _Robert G. Wilson v_, Feb 21 2002