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Search: id:A138171
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| A138171 |
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Odd n where d(n) > d(n+1), where d(n) = number of positive divisors of n. |
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+0
2
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| 45, 81, 105, 117, 165, 225, 261, 273, 297, 315, 325, 333, 345, 357, 385, 405, 435, 441, 465, 477, 495, 513, 525, 555, 561, 567, 585, 595, 621, 625, 627, 651, 675, 693, 705, 715, 765, 777, 795, 801, 825, 837, 855, 861, 885, 891, 897, 915, 925, 945, 957, 975
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Terms calculated by M. F. Hasler.
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MAPLE
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with(numtheory): a:=proc(n) if tau(2*n)<tau(2*n-1) then 2*n-1 else end if end proc: seq(a(n), n=1..500); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 12 2008
with(numtheory): a:=proc (n) if `mod`(n, 2)=1 and tau(n+1) < tau(n) then n else end if end proc: seq(a(n), n=1..1000); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 31 2008
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CROSSREFS
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Cf. A138046, A138172.
Sequence in context: A082452 A049104 A026060 this_sequence A063343 A043184 A039361
Adjacent sequences: A138168 A138169 A138170 this_sequence A138172 A138173 A138174
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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), Mar 03 2008
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