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Search: id:A113760
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| A113760 |
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a(n) is the least number having sum of digits n in base 10 and also exactly n distinct prime factors. |
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+0
1
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| 20, 30, 2002, 100130, 30030, 11030110, 1010011310, 21020110020, 10030101101020, 3003001000200110, 1010211202010010, 10020011010010010210110
(list; graph; listen)
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OFFSET
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2,1
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EXAMPLE
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a(2)=20 since 2+0=2 and 20=2^2*5 has 2 distinct prime factors.
a(5)=100130 since 1+0+0+1+3+0=5 and 100130=2*5*17*19*31 has 5 distinct prime factors.
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MATHEMATICA
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Lk[n_] := Block[{k = 2}, While[n != Plus @@ IntegerDigits[k] || n != Length@FactorInteger@k, k++ ]; k]; L = {}; Do[v = Lk[n]; Print[{n, v}]; AppendTo[L, v], {n, 2, 5}]; L
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CROSSREFS
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Sequence in context: A120210 A166631 A167360 this_sequence A053679 A158844 A077340
Adjacent sequences: A113757 A113758 A113759 this_sequence A113761 A113762 A113763
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KEYWORD
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base,hard,more,nonn
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AUTHOR
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Giovanni Resta (g.resta(AT)iit.cnr.it), Jan 18 2006
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EXTENSIONS
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More terms from Don Reble (djr(AT)nk.ca), Oct 26 2006
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