A374331 Palindromic squarefree semiprimes such that the sum of the two prime factors is also a palindrome.
6, 717, 989, 13231, 15251, 15751, 18281, 19291, 31613, 34043, 35653, 37073, 37673, 38383, 38683, 97079, 98789, 99899, 1115111, 1226221, 1794971, 3525253, 3755573, 3782873, 104646401, 114202411, 127888721, 133707331, 134010431, 137181731, 138050831, 146828641, 157494751, 157585751, 161555161
Offset: 1
Examples
717 is a term because 717 = 3*239 and 3 + 239 = 242.
Programs
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Mathematica
Select[Range[10^6], PalindromeQ[#] && SquareFreeQ[#] && PrimeNu[#]==2 && PalindromeQ[Total[First/@FactorInteger[#]]]&] (* Stefano Spezia, Jul 06 2024 *)
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PARI
ispal(n)=my(d=digits(n));d==Vecrev(d) \\ for(a=2,10^10,if(omega(a)==2&&bigomega(a)==2 &&ispal(a),b=factor(a)[1,1]+factor(a)[2,1]; if(ispal(b),print1(a,","))))
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PARI
isok(k) = if (issquarefree(k) && ispal(k), my(f=factor(k)); (bigomega(f)==2) && ispal(f[1,1]+f[2,1])); \\ Michel Marcus, Jul 05 2024