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 A179826 #9 Jul 16 2022 11:58:43 %S A179826 41,61,2,3,23,43,53,83,5,7,47,67,19,29,59,89,401,601,11,211,811,911, %T A179826 421,521,821,31,331,431,631,41,241,541,641,251,61,461,661,71,271,571, %U A179826 281,881,491,691,2,3,103,503,13,613,23,223,523,823,233,433,43,443,643,53 %N A179826 Primes that can be obtained from composite numbers by interchanging the first and last digits. %C A179826 The composite number must contain at least two digits. %C A179826 Primes may be repeated; the reverted A002808(j) are investigated along increasing j and their trailing zeros become leading zeros and are dropped. [_R. J. Mathar_, Jul 30 2010] %e A179826 41 is a prime from the composite number 14 by interchanging the first and last digit. 47 is a prime from the composite number 74 by interchanging the first and last digit. %t A179826 nonpr=Complement[Range[10,1000],Prime[Range[PrimePi[1000]]]]; %t A179826 swtch[n_]:=Module[{idn=IntegerDigits[n],f,l,m},f=First[idn];l=Last[idn];m=Most[Rest[idn]];FromDigits[Join[{l},m,{f}]]] %t A179826 Select[swtch[#]&/@nonpr,PrimeQ] (* _Harvey P. Dale_, Dec 14 2010 *) %K A179826 base,nonn %O A179826 1,1 %A A179826 _Parthasarathy Nambi_, Jul 29 2010 %E A179826 Minor edits by _N. J. A. Sloane_, Jul 29 2010 %E A179826 More terms from _R. J. Mathar_, Jul 30 2010