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Search: id:A139422
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| A139422 |
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a(1)=a(2)=1. For n>=3, a(n) = a(n-1) + d(a(n-1)) + d(a(n-2)), where d(m) is the number of positive divisors of m. |
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+0
2
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| 1, 1, 3, 6, 12, 22, 32, 42, 56, 72, 92, 110, 124, 138, 152, 168, 192, 222, 244, 258, 272, 290, 308, 328, 348, 368, 390, 416, 444, 468, 498, 524, 538, 548, 558, 576, 609, 638, 654, 670, 686, 702, 726, 754, 774, 794, 810, 834, 862, 874
(list; graph; listen)
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OFFSET
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1,3
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MAPLE
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with(numtheory): a[1]:=1: a[2]:=1: for n from 3 to 50 do a[n]:=a[n-1]+tau(a[n-1])+tau(a[n-2]) end do: seq(a[n], n=1..50); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Apr 26 2008
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CROSSREFS
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Cf. A139423, A064491.
Sequence in context: A092176 A000991 A095093 this_sequence A062483 A081056 A066982
Adjacent sequences: A139419 A139420 A139421 this_sequence A139423 A139424 A139425
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet (qq-quet(AT)mindspring.com), Apr 21 2008
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EXTENSIONS
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More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Apr 26 2008
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