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A238162
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Least common multiple of the prime factors of n, each increased by 1.
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1
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3, 4, 3, 6, 12, 8, 3, 4, 6, 12, 12, 14, 24, 12, 3, 18, 12, 20, 6, 8, 12, 24, 12, 6, 42, 4, 24, 30, 12, 32, 3, 12, 18, 24, 12, 38, 60, 28, 6, 42, 24, 44, 12, 12, 24, 48, 12, 8, 6, 36, 42, 54, 12, 12, 24, 20, 30, 60, 12, 62, 96, 8, 3, 42, 12, 68, 18, 24, 24, 72, 12, 74, 114, 12, 60, 24, 84, 80, 6, 4, 42, 84, 24, 18, 132, 60, 12, 90, 12, 56, 24, 32, 48, 60, 12, 98, 24, 12, 6
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OFFSET
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2,1
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COMMENTS
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If n is a composite squarefree number and a(n) divides n+1, then n is a Lucas-Carmichael number (A006972). - Daniel Suteu, Oct 02 2022
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LINKS
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EXAMPLE
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The prime factors of 6 are 2 and 3, which become 3 and 4 when respectively increased by 1, and lcm(3, 4) = 12. Therefore, a(6) = 12.
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PROG
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(PARI) a(n) = my(f=factor(n)); lcm(vector(#f~, k, f[k, 1]+1)); \\ Daniel Suteu, Oct 02 2022
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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