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Search: id:A143322
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| A143322 |
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A positive integer n is included if the sum of the distinct prime divisors of n divides n-1. |
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2
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| 6, 21, 28, 36, 50, 96, 99, 216, 225, 301, 325, 352, 400, 441, 486, 495, 496, 576, 630, 676, 697, 784, 847, 925, 1225, 1296, 1333, 1521, 1536, 1587, 1695, 1701, 1792, 1909, 2025, 2041, 2133, 2145, 2500, 2601, 2624, 2916, 2926, 3025, 3200, 3220, 3276, 3456
(list; graph; listen)
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OFFSET
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1,1
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LINKS
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Leroy Quet, Home Page (listed in lieu of email address)
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EXAMPLE
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The distinct primes dividing 28 are 2 and 7, since 28 is factored as 2^2 *7^1. 2+7=9 is a divisor of 28-1 = 27. So 28 is included in this sequence.
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MAPLE
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with(numtheory): a:=proc(n) local f: f:= factorset(n): if `mod`(n-1, add(f[i], i=1..nops(f)))=0 then n else end if end proc: seq(a(n), n=2..4000); [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Aug 16 2008]
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CROSSREFS
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Cf. A008472, A089352, A143321.
Sequence in context: A020880 A046467 A132184 this_sequence A034897 A064440 A106634
Adjacent sequences: A143319 A143320 A143321 this_sequence A143323 A143324 A143325
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet Aug 07 2008
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EXTENSIONS
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Extended by Emeric Deutsch (deutsch(AT)duke.poly.edu), Aug 16 2008
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