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A181639
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Numbers n such that omega(n) = digit-reverse(n).
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0
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20, 30, 200, 300, 2000, 3000, 20000, 30000, 200000, 300000, 2000000, 3000000, 20000000, 30000000
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OFFSET
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1,1
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COMMENTS
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omega(n) = A001221(n) is the number of distinct primes dividing n.
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LINKS
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FORMULA
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EXAMPLE
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300 is in the sequence because omega(300) = reversal(300) = 3.
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MATHEMATICA
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Do[If[Length[ FactorInteger[ n ]]==FromDigits[Reverse[IntegerDigits[n]]], Print[n]],
{n, 1, 10^9}]
Select[Range[10^9], PrimeNu[#]==FromDigits[Reverse[IntegerDigits[#]]]&] (* or *) Flatten[Table[{2*10^n, 3*10^n}, {n, 10}]] (* Harvey P. Dale, Dec 17 2013 *)
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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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