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A158851
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a(n) = lcm(1,2,3,...,n) mod (n+1).
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2
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1, 2, 2, 2, 0, 4, 4, 3, 0, 1, 0, 4, 0, 0, 8, 5, 0, 14, 0, 0, 0, 15, 0, 5, 0, 18, 0, 1, 0, 20, 16, 0, 0, 0, 0, 2, 0, 0, 0, 15, 0, 15, 0, 0, 0, 8, 0, 21, 0, 0, 0, 29, 0, 0, 0, 0, 0, 21, 0, 16, 0, 0, 32, 0, 0, 29, 0, 0, 0, 23, 0, 22, 0, 0, 0, 0, 0, 30, 0, 54, 0, 71, 0, 0, 0, 0, 0, 37, 0, 0, 0, 0, 0, 0, 0, 7, 0
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OFFSET
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1,2
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COMMENTS
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If n+1 is not a power of a prime, then a(n) = 0.
If n+1 = p^m, p = prime, then p^(m-1) (= (n+1)/p) divides a(n), but p^m (= n+1) does not divide a(n).
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LINKS
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FORMULA
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EXAMPLE
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a(6) = lcm(1,2,3,4,5,6) mod (6+1) = 60 mod 7 = 4.
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MAPLE
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a := proc (n) options operator, arrow: `mod`(lcm(seq(j, j = 1 .. n)), n+1) end proc: seq(a(n), n = 1 .. 100); # Emeric Deutsch, Apr 03 2009
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MATHEMATICA
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PROG
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(PARI) a(n) = lcm(vector(n, k, k)) % (n+1); \\ Michel Marcus, Mar 06 2018
(GAP) List([1..100], n->Lcm([1..n]) mod (n+1)); # Muniru A Asiru, Mar 06 2018
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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