A046354 -id:A046354 - cp's OEIS frontend

A046352 Composite numbers whose sum of prime factors is palindromic (counted with multiplicity).

4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 24, 27, 28, 40, 45, 48, 54, 57, 62, 85, 102, 106, 116, 121, 123, 182, 194, 218, 259, 260, 278, 292, 298, 305, 308, 312, 351, 358, 366, 370, 388, 403, 413, 415, 428, 440, 444, 483, 495, 498, 508, 528, 548, 568, 575, 590

Offset: 1

Patrick De Geest, Jun 15 1998

			116 = 2 * 2 * 29 -> 2 + 2 + 29 = 33 and 33 is a palindrome.

R. J. Mathar, Table of n, a(n) for n = 1..2014

Cf. A046353, A046354.

n := 1 ;
for i from 2 to 30000 do
    if not isprime(i) then
        sof := A001414(i) ;
        if isA002113(sof) then
            printf("%d %d\n",n,i) ;
            n := n+1 ;
        end if;
    end if;
end do: # R. J. Mathar, Sep 09 2015

palQ[n_]:=Reverse[x=IntegerDigits[n]]==x; Select[Range[4,590],!PrimeQ[#]&&palQ[Total[Times@@@FactorInteger[#]]]&] (* Jayanta Basu, Jun 05 2013 *)
Select[Range@1000,CompositeQ@#&&PalindromeQ[Dot@@Transpose[FactorInteger@#]]&]  (* Hans Rudolf Widmer, Dec 21 2022 *)

A046353 Odd composite numbers whose sum of prime factors is palindromic (counted with multiplicity).

Original entry on oeis.org

9, 15, 27, 45, 57, 85, 121, 123, 259, 305, 351, 403, 413, 415, 483, 495, 575, 597, 627, 639, 663, 687, 689, 705, 717, 735, 807, 875, 893, 931, 935, 985, 989, 1073, 1135, 1183, 1203, 1207, 1263, 1285, 1293, 1331, 1353, 1383, 1385, 1407, 1473, 1505, 1545

Offset: 1

Patrick De Geest, Jun 15 1998

			689 = 13 * 53 -> 13 + 53 = 66 and 66 is a palindrome.

John Cerkan, Table of n, a(n) for n = 1..10000

Cf. A046352, A046354.

palQ[n_]:=Reverse[x=IntegerDigits[n]]==x; Select[Range[9,1545,2],!PrimeQ[#]&&palQ[Total[Times@@@FactorInteger[#]]]&] (* Jayanta Basu, Jun 05 2013 *)

from sympy import factorint
def is_046353(n):
    if n % 2 == 0: return False
    f = factorint(n)
    if sum([f[i] for i in f]) < 2: return False
    sfa = sum([i*f[i] for i in f])
    if sfa == int(str(sfa)[::-1]): return True
    return False # John Cerkan, Apr 24 2018

Name clarified and offset changed by John Cerkan, Apr 24 2018

cp's OEIS Frontend

A046352 Composite numbers whose sum of prime factors is palindromic (counted with multiplicity).

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