A046352 Composite numbers whose sum of prime factors is palindromic (counted with multiplicity).

4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 24, 27, 28, 40, 45, 48, 54, 57, 62, 85, 102, 106, 116, 121, 123, 182, 194, 218, 259, 260, 278, 292, 298, 305, 308, 312, 351, 358, 366, 370, 388, 403, 413, 415, 428, 440, 444, 483, 495, 498, 508, 528, 548, 568, 575, 590

Offset: 1

Author

Patrick De Geest, Jun 15 1998

Keywords

• nonn
• base

Examples

			116 = 2 * 2 * 29 -> 2 + 2 + 29 = 33 and 33 is a palindrome.
		

Links

• R. J. Mathar, Table of n, a(n) for n = 1..2014

Crossrefs

Cf. A046353, A046354.

Programs

Maple

n := 1 ;
for i from 2 to 30000 do
    if not isprime(i) then
        sof := A001414(i) ;
        if isA002113(sof) then
            printf("%d %d\n",n,i) ;
            n := n+1 ;
        end if;
    end if;
end do: # R. J. Mathar, Sep 09 2015

Mathematica

palQ[n_]:=Reverse[x=IntegerDigits[n]]==x; Select[Range[4,590],!PrimeQ[#]&&palQ[Total[Times@@@FactorInteger[#]]]&] (* Jayanta Basu, Jun 05 2013 *)
Select[Range@1000,CompositeQ@#&&PalindromeQ[Dot@@Transpose[FactorInteger@#]]&]  (* Hans Rudolf Widmer, Dec 21 2022 *)