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Search: id:A099642
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| A099642 |
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a(n) is the smallest composite solution to tau[x+n]=tau[x]+n, where tau[]~A000005[], the number of divisors. |
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+0
1
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| 1, 10, 9, 26, 25, 74, 169, 82, 441, 170, 133, 348, 6889, 166, 3025, 344, 559, 1602, 9981, 820, 9979, 986, 4333, 1236, 9191, 694, 3249, 1652, 3481, 9378, 34969, 3118, 859329, 5636, 36829, 3324, 51947, 3994, 6561, 5000, 15835, 16806, 944741, 6436, 119025
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OFFSET
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1,2
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EXAMPLE
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n=5: a(5)=25 because tau(25)+5=3+5=8=tau(25+5)=tau(30)
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MATHEMATICA
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ds[x_, de_] :=DivisorSigma[0, x+de]-DivisorSigma[0, x]-de; a[n_] :=Block[{m=1, s=ds[m, n]}, While[(s!=0||PrimeQ[m])&&!Greater[m, 10000000], m++ ]; m];
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CROSSREFS
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Cf. A000005, A054905.
Sequence in context: A063661 A063596 A003568 this_sequence A052196 A070252 A038311
Adjacent sequences: A099639 A099640 A099641 this_sequence A099643 A099644 A099645
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Nov 02 2004
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