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A073545
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Least k such that 1/tau(k) + 1/tau(k+1) + 1/tau(k+2) + ... + 1/tau(k+n) is equal to 1 (where tau(k)=A000005(k) is the number of divisors of k).
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0
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1, 2, 6, 25, 54, 243, 1204, 3549, 19544, 81829, 104663, 663490, 743764, 7925355, 15376922, 39462786, 201432540, 1187707803, 3034296474, 8657654859, 48511905236, 154669032693, 123533546264
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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EXAMPLE
| a(2)=6 because 1/tau(6)+1/tau(7)+1/tau(8) = 1/4+1/2+1/4 = 1.
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MATHEMATICA
| a[n_] := For[k=1, True, k++, If[Sum[1/DivisorSigma[0, k+i], {i, 0, n}]==1, Return[k]]]
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CROSSREFS
| Sequence in context: A123150 A086591 A173609 * A103063 A030228 A066317
Adjacent sequences: A073542 A073543 A073544 * A073546 A073547 A073548
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KEYWORD
| nonn
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AUTHOR
| Benoit Cloitre (benoit7848c(AT)orange.fr), Aug 27 2002
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EXTENSIONS
| Edited by Dean Hickerson (dean.hickerson(AT)yahoo.com), Sep 03 2002
2 more terms from Ryan Propper (rpropper(AT)stanford.edu), Sep 04 2005
a(14)-a(22) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Jun 23 2010
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