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Non-semiprimes whose reversal is a prime.
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%I #7 Feb 06 2019 00:39:15

%S 2,3,5,7,11,13,16,17,20,30,31,32,37,50,70,71,73,76,79,92,97,98,101,

%T 104,107,110,112,113,124,125,128,130,131,136,140,149,151,152,157,160,

%U 164,167,170,172,175,179,181,182,188,191,196,199,200,300,310,311,313,316

%N Non-semiprimes whose reversal is a prime.

%p A100959 := proc(n) option remember ; if n <= 3 then n ; else for a from procname(n-1)+1 do if numtheory[bigomega](a) <> 2 then return a; end if; end do: end if: end proc: read("transforms") ; for n from 1 to 300 do c := A100959(n) ; if isprime(digrev(c)) then printf("%d,",c) ; end if; end do: # _R. J. Mathar_, Apr 27 2010

%t Select[Range[400],PrimeOmega[#]!=2&&PrimeQ[FromDigits[Reverse[ IntegerDigits[ #]]]]&] (* _Harvey P. Dale_, Jan 03 2015 *)

%Y Cf. A100959.

%K nonn,base

%O 1,1

%A _Juri-Stepan Gerasimov_, Apr 20 2010

%E Corrected (20, 30, 50, 70, 76, 92, 110, 128, etc. inserted) by _R. J. Mathar_, Apr 27 2010