A046356 -id:A046356 - cp's OEIS frontend

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

Patrick De Geest, Jun 15 1998

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

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

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

Cf. A046356, A046357.

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

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 *)

A046357 Composite palindromes with only palindromic prime factors whose sum is palindromic (counted with multiplicity).

Original entry on oeis.org

4, 6, 8, 9, 121, 1331, 5445, 10201, 13231, 14641, 15251, 18281, 19291, 31613, 35653, 37673, 38683, 52525, 59895, 1030301, 1336331, 3192913, 8117118, 104060401, 134969431, 286121682, 319464913, 677707776

Offset: 1

Patrick De Geest, Jun 15 1998

			319464913 = 10301 * 31013 and 10301 + 31013 = 41314 and all are palindromic.

Cf. A046355, A046356.

palQ[n_]:= Reverse[x=IntegerDigits[n]] == x; t={}; Do[If[!PrimeQ[n] && And@@palQ/@Join[{n, Total[Times@@@(x=FactorInteger[n])]}, First/@x], AppendTo[t,n]],{n, 2, 3.2*10^6}]; t (* Jayanta Basu, Jun 05 2013 *)

A046355 INTERSECT A002113. - R. J. Mathar, Sep 09 2015

cp's OEIS Frontend

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

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