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A258324 Least common multiple of all n - d, where d < n and d is a divisor of n. 2
1, 1, 2, 6, 4, 60, 6, 84, 24, 360, 10, 3960, 12, 1092, 420, 840, 16, 12240, 18, 13680, 1260, 4620, 22, 1275120, 120, 7800, 936, 19656, 28, 1096200, 30, 52080, 5280, 17952, 7140, 5654880, 36, 25308, 8892, 2489760, 40, 1343160, 42, 397320, 27720 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

a(n) is a divisor of A072513(n).

a(n) = n-1 if and only if n is prime. - Robert Israel, May 26 2015

LINKS

Ivan Neretin, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = lcm(n-d_1, n-d_2, ..., n-d_k) where d_i are the aliquot divisors of n.

EXAMPLE

a(9) = lcm(9-1, 9-3) = lcm(8, 6) = 24.

MAPLE

f:= n -> ilcm(seq(n-d, d = numtheory:-divisors(n) minus {n})):

map(f, [$ 1 .. 100]); # Robert Israel, May 26 2015

MATHEMATICA

Table[If[n == 1, 1, LCM @@ (n - Most[Divisors[n]])], {n, 50}]

PROG

(PARI) a(n)=lcm(apply(d->if(d<n, n-d, 1), divisors(n))) \\ Charles R Greathouse IV, May 26 2015

(Haskell)

a258324 n = foldl lcm 1 $ map (n -) $ a027751_row n

-- Reinhard Zumkeller, May 27 2015

CROSSREFS

Cf. A072513 (product instead of LCM).

Cf. A027751.

Sequence in context: A264609 A126262 A330078 * A080499 A072513 A022404

Adjacent sequences:  A258321 A258322 A258323 * A258325 A258326 A258327

KEYWORD

nonn

AUTHOR

Ivan Neretin, May 26 2015

STATUS

approved

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Last modified August 10 06:42 EDT 2020. Contains 336368 sequences. (Running on oeis4.)