A046354 Composite palindromes whose sum of prime factors is palindromic (counted with multiplicity).

4, 6, 8, 9, 121, 292, 444, 575, 717, 828, 989, 1331, 2002, 4884, 5445, 8668, 9559, 10201, 11211, 11811, 13231, 14241, 14541, 14641, 15251, 15751, 16261, 16761, 18281, 19291, 19591, 20002, 21112, 21312, 22022, 22922, 23832, 26062, 26162

Offset: 1

Author

Patrick De Geest, Jun 15 1998

Keywords

• nonn
• base

Examples

			15751 = 19 * 829 -> 19 + 829 = 848 and 848 is a palindrome.
		

Links

• R. J. Mathar and Giovanni Resta, Table of n, a(n) for n = 1..10000 (first 681 terms from R. J. Mathar)

Crossrefs

Cf. A046352, A046353.

Programs

Maple

n := 1 ;
for i from 3 to 30000 do
    pal := A002113(i) ;
    if not isprime(pal) then
        sof := A001414(pal) ;
        if isA002113(sof) then
            printf("%d %d\n",n,pal) ;
            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[4,26170],!PrimeQ[#]&&And@@palQ/@{#,Total[Times@@@FactorInteger[#]]}&](* Jayanta Basu, Jun 05 2013 *)

Formula

A046352 INTERSECT A002113. - R. J. Mathar, Sep 09 2015