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Search: id:A049418
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| A049418 |
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3-i-sigma(n): sum of 3-infinitary divisors of n: if n=Product p(i)^r(i) and d=Product p(i)^s(i), each s(i) has a digit a<=b in its ternary expansion everywhere that the corresponding r(i) has a digit b, then d is a 3-i-divisor of n. |
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+0
1
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| 1, 3, 4, 7, 6, 12, 8, 9, 13, 18, 12, 28, 14, 24, 24, 27, 18, 39, 20, 42, 32, 36, 24, 36, 31, 42, 28, 56, 30, 72, 32, 63, 48, 54, 48, 91, 38, 60, 56, 54, 42, 96, 44, 84, 78, 72, 48, 108, 57, 93, 72, 98, 54, 84, 72, 72, 80, 90, 60, 168, 62, 96, 104, 73, 84, 144, 68, 126, 96
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Multiplicative. If e = sum_{k >= 0} d_k 3^k (base 3 representation), then a(p^e) = prod_{k >= 0} (p^(3^k*{d_k+1}) - 1)/(p^(3^k) - 1). Christian G. Bower (bowerc(AT)usa.net) and Mitch Harris (Harris.Mitchell(AT)mgh.harvard.edu) May 20, 2005.
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LINKS
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J. O. M. Pedersen, Tables of Aliquot Cycles
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CROSSREFS
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Sequence in context: A113957 A073185 A073183 this_sequence A051378 A116607 A107749
Adjacent sequences: A049415 A049416 A049417 this_sequence A049419 A049420 A049421
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KEYWORD
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nonn,nice,easy,mult
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AUTHOR
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Yasutoshi Kohmoto (zbi74583(AT)boat.zero.ad.jp)
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EXTENSIONS
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More terms from Naohiro Nomoto (n_nomoto(AT)yabumi.com), Sep 10 2001
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