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Search: id:A062249
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| A062249 |
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n + d(n), where d(n) = number of divisors of n, cf. A000005. |
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+0
7
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| 2, 4, 5, 7, 7, 10, 9, 12, 12, 14, 13, 18, 15, 18, 19, 21, 19, 24, 21, 26, 25, 26, 25, 32, 28, 30, 31, 34, 31, 38, 33, 38, 37, 38, 39, 45, 39, 42, 43, 48, 43, 50, 45, 50, 51, 50, 49, 58, 52, 56, 55, 58, 55, 62, 59, 64, 61, 62, 61, 72, 63, 66, 69, 71, 69, 74, 69, 74, 73, 78, 73
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Number of cyclic subgroups of dihedral group with 2n elements.
Alternate definition: nth smallest number not a divisor of n - JIMMY (jhbubby(AT)mindspring.com), Apr 06 2008
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LINKS
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Harry J. Smith, Table of n, a(n) for n=1,...,1000
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FORMULA
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a(n) = n + A000005(n). [From Omar E. Pol (info(AT)polprimos.com), Dec 12 2008]
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MAPLE
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with(numtheory):seq(n+tau(n), n=1..71) ; - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jun 04 2008
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PROGRAM
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(PARI) { for (n=1, 1000, write("b062249.txt", n, " ", n + numdiv(n)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Aug 03 2009]
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CROSSREFS
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Cf. A007503, A060710, A000005, A049820.
Sequence in context: A140203 A085888 A112233 this_sequence A081404 A081516 A141425
Adjacent sequences: A062246 A062247 A062248 this_sequence A062250 A062251 A062252
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KEYWORD
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nonn
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AUTHOR
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Ahmed Fares (ahmedfares(AT)my-deja.com), Jul 01 2001
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EXTENSIONS
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Formula and more terms from Vladeta Jovovic (vladeta(AT)eunet.rs), Jul 03 2001
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