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Search: id:A096217
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| A096217 |
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a(n) = sum of terms of {a(1),a(2),a(3),...a(n-1)} which are coprime to n. |
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+0
1
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| 1, 1, 2, 2, 6, 2, 14, 2, 24, 2, 56, 2, 114, 2, 86, 2, 318, 2, 524, 2, 632, 2, 1798, 2, 3598, 2, 6736, 2, 12138, 2, 24278, 2, 37756, 2, 72308, 2, 160424, 2, 308250, 2, 629102, 2, 1258120, 2, 937358, 2, 3453688, 2, 3437884, 2, 9395312, 2, 18802902, 2, 36816688, 2
(list; graph; listen)
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OFFSET
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1,3
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COMMENT
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a(n) is 2 if n is an even integer >= 4.
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EXAMPLE
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a(1)=1, a(2)=1, a(3)=2, a(4)=2, a(6)=2, a(7)=14, and a(8)=2 are the terms, prior to a(9), which are coprime to 9. So a(9) = 1 +1 +2 +2 +2 +14 +2 = 24.
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MATHEMATICA
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a[1] = 1; a[n_] := a[n] = Plus @@ (a /@ Select[Range[n - 1], GCD[ a[ # ], n] == 1 &]); Table[ a[n], {n, 56}] (from Robert G. Wilson v Jul 31 2004)
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CROSSREFS
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Sequence in context: A091818 A071223 A055934 this_sequence A057562 A102628 A036655
Adjacent sequences: A096214 A096215 A096216 this_sequence A096218 A096219 A096220
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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), Jul 28 2004
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EXTENSIONS
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Edited and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Jul 31 2004
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