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Search: id:A153825
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| A153825 |
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Sum of proper divisors minus the number of proper divisors of n!. |
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+0
2
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| 0, 0, 0, 3, 29, 225, 1669, 14245, 118705, 1118001, 11705019, 144091717, 1738439017, 24817157329, 355309322689, 5378578597729, 86081749391905, 1570394279028289, 28281459220178401, 572031558109560385, 11458497230555053681
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OFFSET
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0,4
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COMMENT
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a(n) is the sum of proper divisors minus the number of proper divisors of factorial number A000142(n).
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FORMULA
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a(n) = A153824(n)-A153823(n) = A152770(A000142(n)).
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MAPLE
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with(numtheory): seq(sigma(factorial(n))-factorial(n)-tau(factorial(n))+1, n = 0 .. 22); [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Jan 07 2009]
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CROSSREFS
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Cf. A000005, A000142, A000203, A001065, A032741, A062569, A152770, A153823, A153824.
Sequence in context: A118584 A126185 A083092 this_sequence A135163 A074366 A037791
Adjacent sequences: A153822 A153823 A153824 this_sequence A153826 A153827 A153828
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KEYWORD
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nonn
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AUTHOR
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Omar E. Pol (info(AT)polprimos.com), Jan 02 2009
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EXTENSIONS
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Extended by Emeric Deutsch (deutsch(AT)duke.poly.edu), Jan 07 2009
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