|
%I #11 Feb 02 2019 18:49:34
%S 13,29,31,41,47,53,61,79,83,97,103,107,113,131,163,181,227,229,239,
%T 241,257,269,277,281,293,307,311,313,331,353,383,421,431,449,457,461,
%U 463,467,479,499,503,523,547,557,563,577,587,607,613,631,641,643,647,653
%N Prime numbers p such that (the largest digit of p) - (the smallest digit of p) is prime.
%H Harvey P. Dale, <a href="/A158075/b158075.txt">Table of n, a(n) for n = 1..1000</a>
%e 13 (3-1=2), 29 (9-2=7), 31 (3-1=2), 47 (7-4=3), 53 (5-3=2), etc.
%p a := proc (n) local nn, nnn: nn := convert(ithprime(n), base, 10): nnn := seq(nn[j], j = 1 .. nops(nn)): if isprime(max(nnn)-min(nnn)) then ithprime(n) end if end proc: seq(a(n), n = 1 .. 150); # _Emeric Deutsch_, Apr 01 2009
%t ldsdpQ[n_]:=Module[{idn=IntegerDigits[n]},PrimeQ[Max[idn]-Min[idn]]]; Select[Prime[Range[200]],ldsdpQ] (* _Harvey P. Dale_, Jun 10 2013 *)
%K nonn,base,less
%O 1,1
%A _Juri-Stepan Gerasimov_, Mar 12 2009
%E Missing terms (61,281,449,457,461,463,467,479,727,757,769) added by _Emeric Deutsch_, Apr 01 2009
|
