This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A077360 #16 May 12 2024 11:47:44 %S A077360 127,131,137,139,151,157,173,179,223,229,233,239,331,337,421,431,433, %T A077360 457,523,631,677,733,739,751,773,823,829,839,853,859,937,977,1021, %U A077360 1031,1033,1039,1051,1117,1171,1193,1231,1237,1291,1297,1319,1373,1433,1439 %N A077360 Primes whose external digits as well as internal digits form a prime. %C A077360 Intersection of A069686 and A077359. %H A077360 Jason Yuen, <a href="/A077360/b077360.txt">Table of n, a(n) for n = 1..10000</a> %e A077360 139 is a term as 19 and 3 are both primes. %o A077360 (PARI) forprime(p=1,1440,if(isprime(indigs(p))&&isprime(exdigs(p)),print1(p,","))) %o A077360 (Python) %o A077360 from sympy import isprime, primerange %o A077360 for p in primerange(100, 1440): %o A077360 if isprime(int(str(p)[1:-1])) and isprime(int(str(p)[0]+str(p)[-1])): %o A077360 print(p) # _Jason Yuen_, Apr 21 2024 %Y A077360 Cf. A069686, A077359. %K A077360 base,nonn,easy %O A077360 1,1 %A A077360 _Amarnath Murthy_, Nov 05 2002 %E A077360 Edited and extended by _Klaus Brockhaus_, Nov 06 2002