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

1,1

Comments

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

Links

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

Example

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

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 *)

Crossrefs

Cf. A046356, A046357.

Sequence in context: A070807 A246282 A046352 * A335419 A163122 A329149

Adjacent sequences: A046352 A046353 A046354 * A046356 A046357 A046358

Keyword

nonn,base

Author

Patrick De Geest, Jun 15 1998

Status

approved