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A046352
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Composite numbers whose sum of prime factors is palindromic (counted with multiplicity).
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4
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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
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OFFSET
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1,1
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LINKS
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EXAMPLE
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116 = 2 * 2 * 29 -> 2 + 2 + 29 = 33 and 33 is a palindrome.
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MAPLE
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n := 1 ;
for i from 2 to 30000 do
if not isprime(i) then
if isA002113(sof) then
printf("%d %d\n", n, i) ;
n := n+1 ;
end if;
end if;
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MATHEMATICA
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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 *)
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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