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%I #9 Jul 16 2022 11:58:43
%S 41,61,2,3,23,43,53,83,5,7,47,67,19,29,59,89,401,601,11,211,811,911,
%T 421,521,821,31,331,431,631,41,241,541,641,251,61,461,661,71,271,571,
%U 281,881,491,691,2,3,103,503,13,613,23,223,523,823,233,433,43,443,643,53
%N Primes that can be obtained from composite numbers by interchanging the first and last digits.
%C The composite number must contain at least two digits.
%C 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 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 nonpr=Complement[Range[10,1000],Prime[Range[PrimePi[1000]]]];
%t 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 Select[swtch[#]&/@nonpr,PrimeQ] (* _Harvey P. Dale_, Dec 14 2010 *)
%K base,nonn
%O 1,1
%A _Parthasarathy Nambi_, Jul 29 2010
%E Minor edits by _N. J. A. Sloane_, Jul 29 2010
%E More terms from _R. J. Mathar_, Jul 30 2010
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