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%I #18 Apr 05 2020 13:33:34
%S 0,3,5,8,9,15,17,18,20,23,29,30,32,36,38,45,47,48,51,53,57,60,62,72,
%T 74,80,81,83,86,87,90,93,95,107,113,116,117,125,126,131,132,135,141,
%U 147,149,155,162,168,170,173,180,182,183,194,197,198,201,204,207,210
%N Numbers k such that k surrounded by digit '1' is a prime.
%H Daniel Starodubtsev, <a href="/A032682/b032682.txt">Table of n, a(n) for n = 1..10000</a>
%p t0:=[]; u0:=[]; for n from 1 to 100 do t1:=cat(1,n,1); t1:=convert(t1,decimal,10); if isprime(t1) then t0:=[op(t0),n]; u0:=[op(u0),t1]; fi; od: t0;
%t Select[Range[0,210],PrimeQ[FromDigits[Join[{1},IntegerDigits[#],{1}]]]&] (* _Jayanta Basu_, Jun 02 2013 *)
%o (Python)
%o from sympy import isprime
%o print([i for i in range(200) if isprime(int('1' + str(i) + '1'))]) # _Daniel Starodubtsev_, Apr 05 2020
%Y The primes are in A099677. Cf. A032686.
%K nonn,base
%O 1,2
%A _Patrick De Geest_, May 15 1998
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