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Search: id:A139423
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| A139423 |
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a(1)=1, a(2)=2. 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, 2, 5, 9, 14, 21, 29, 35, 41, 47, 51, 57, 65, 73, 79, 83, 87, 93, 101, 107, 111, 117, 127, 135, 145, 157, 163, 167, 171, 179, 187, 193, 199, 203, 209, 217, 225, 238, 255, 271, 281, 285, 295, 307, 313, 317, 321, 327, 335, 343
(list; graph; listen)
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OFFSET
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1,2
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MAPLE
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with(numtheory): a[1]:=1: a[2]:=2: 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 30 2008
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CROSSREFS
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Cf. A139422, A064491.
Sequence in context: A048093 A024669 A006482 this_sequence A026053 A011905 A098065
Adjacent sequences: A139420 A139421 A139422 this_sequence A139424 A139425 A139426
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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 30 2008
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