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Search: id:A085020
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| A085020 |
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Sum of divisors d+1 of n if d+1 is prime. |
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+0
4
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| 2, 5, 2, 10, 2, 12, 2, 10, 2, 16, 2, 30, 2, 5, 2, 27, 2, 31, 2, 21, 2, 28, 2, 30, 2, 5, 2, 39, 2, 54, 2, 27, 2, 5, 2, 86, 2, 5, 2, 62, 2, 55, 2, 33, 2, 52, 2, 47, 2, 16, 2, 63, 2, 31, 2, 39, 2, 64, 2, 133, 2, 5, 2, 27, 2, 102, 2, 10, 2, 87, 2, 159, 2, 5, 2, 10, 2, 91, 2, 79, 2, 88, 2, 102, 2, 5
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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a(18) = 31 because the divisors of 18 are [1, 2, 3, 6, 9, 18]
and 2+3+7+19 = 31.
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MAPLE
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T := proc(n, k) local i; numtheory[divisors](n); select(isprime, map(i->i+k, %)); add(i, i=%) end: seq(T(n+1, 1), n=0..20); [From Peter Luschny (peter(AT)luschny.de), May 04 2009]
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CROSSREFS
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Cf. A067513.
Cf. A008472 [From Peter Luschny (peter(AT)luschny.de), May 04 2009]
Sequence in context: A131201 A070633 A119764 this_sequence A102469 A098886 A089120
Adjacent sequences: A085017 A085018 A085019 this_sequence A085021 A085022 A085023
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KEYWORD
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easy,nonn
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AUTHOR
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Jason Earls (zevi_35711(AT)yahoo.com), Jun 18 2003
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