A046355 Composite numbers with only palindromic prime factors whose sum is palindromic (counted with multiplicity).

4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 24, 27, 28, 40, 45, 48, 54, 121, 308, 440, 495, 528, 594, 735, 784, 875, 882, 1050, 1120, 1250, 1260, 1331, 1344, 1500, 1512, 1600, 1701, 1800, 1920, 2025, 2048, 2101, 2121, 2160, 2304, 2430, 2525, 2592, 2751, 2916, 3030

Offset: 1

Author

Patrick De Geest, Jun 15 1998

Keywords

• nonn
• base

Comments

Subsequence of the numbers k in A046349 such that A262049(k) is in A002113. - R. J. Mathar, Sep 09 2015

Examples

			3030 = 2 * 3 * 5 * 101 -> 2 + 3 + 5 + 101 = 111 and 111 is a palindrome.
		

Links

• Giovanni Resta, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A046356, A046357.

Programs

Maple

isA046355 := proc(n)
    local sofpp ;
    if isA046349(n) then
        sofpp := A262049(n) ;
        isA002113(sofpp) ;
    else
        false;
    end if;
end proc:
for n from 2 to 400 do
    if isA046355(n) then
        printf("%d,",n);
    end if;
end do: # R. J. Mathar, Sep 09 2015

Mathematica

palQ[n_] := Reverse[x=IntegerDigits[n]] == x; Select[Range[4,3100], !PrimeQ[#] && And@@palQ/@Join[{Total[Times@@@(x=FactorInteger[#])]}, First/@x]&] (* Jayanta Basu, Jun 05 2013 *)