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A046453
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Composite numbers n such that concatenation of the 4 prime factors of n is a palindrome.
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0
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16, 81, 625, 2401, 3975, 4719, 5565, 6591, 8745, 10731, 14399, 14641, 16863, 20111, 34391, 36501, 39963, 41019, 46179, 47229, 48231, 60813, 61761, 62991, 69027, 109179, 113631, 116475, 143991, 158985, 159777, 162409, 164145, 167571, 183159, 184065
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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EXAMPLE
| E.g. 164145 = 3 * 5 * 31 * 353 -> 3531353 is palindromic.
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MATHEMATICA
| pal4Q[n_]:=Module[{ds=Flatten[IntegerDigits/@(Table[First[#], {Last[ #]}]&/@ FactorInteger[n])]}, PrimeOmega[n]==4&&ds==Reverse[ds]]; Select[ Range[190000], pal4Q] (* From Harvey P. Dale, Nov 12 2011 *)
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CROSSREFS
| Cf. A046447.
Sequence in context: A108941 A153157 A113849 * A030514 A056571 A053909
Adjacent sequences: A046450 A046451 A046452 * A046454 A046455 A046456
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KEYWORD
| nonn,base
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AUTHOR
| Patrick De Geest (pdg(AT)worldofnumbers.com), Jul 15 1998.
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EXTENSIONS
| One more term from Harvey P. Dale, Nov 12 2011
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