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

1,1

Links

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

Formula

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

Example

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

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 *)

Crossrefs

Cf. A046352, A046353.

Sequence in context: A232541 A076612 A182775 * A046357 A227947 A144123

Adjacent sequences: A046351 A046352 A046353 * A046355 A046356 A046357

Keyword

nonn,base

Author

Patrick De Geest, Jun 15 1998

Status

approved