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Search: id:A113758
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| A113758 |
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a(n) is the least number having sum of digits n in base 10 and also exactly n prime factors (counted with multiplicity). |
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+0
1
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| 10001, 12, 40, 32, 240, 3040, 2240, 1152, 6400, 12800, 21504, 440320, 2140160, 172032, 4710400, 1802240, 1327104, 20316160, 40632320, 17301504, 152043520
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OFFSET
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2,1
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EXAMPLE
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a(2)=10001 since 1+0+0+0+1=2 and 10001=73*137 has 2 prime factors.
a(3)=12 since 1+2=3 and 12=2*2*3 has 3 prime factors.
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MATHEMATICA
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Lk[n_] := Block[{k = 2}, While[n != Plus @@ IntegerDigits[k] || n != Plus @@ (Transpose[FactorInteger@k][[2]]), k++ ]; k]; L = {}; Do[v = Lk[n]; Print[{n, v}]; AppendTo[L, v], {n, 2, 13}]; L
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CROSSREFS
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Cf. A115156.
Sequence in context: A017644 A013857 A091566 this_sequence A115850 A082567 A031688
Adjacent sequences: A113755 A113756 A113757 this_sequence A113759 A113760 A113761
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KEYWORD
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base,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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