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A057643 Least common multiple of all (k+1)'s, where the k's are the positive divisors of n. 8
2, 6, 4, 30, 6, 84, 8, 90, 20, 66, 12, 5460, 14, 120, 48, 1530, 18, 7980, 20, 2310, 88, 276, 24, 81900, 78, 378, 140, 3480, 30, 114576, 32, 16830, 204, 630, 72, 3838380, 38, 780, 280, 284130, 42, 397320, 44, 4140, 5520, 1128, 48, 9746100, 200, 14586, 468 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(n) is a divisor of A020696(n). - Ivan Neretin, May 27 2015

LINKS

Carl R. White, Table of n, a(n) for n = 1..10000

EXAMPLE

Since the positive divisors of 6 are 1, 2, 3 and 6, a(6) = LCM(1+1,2+1,3+1,6+1) = LCM(2,3,4,7) = 84.

MAPLE

f:= n -> ilcm(op(map(`+`, numtheory:-divisors(n), 1)));

seq(f(n), n=1..100); # Robert Israel, Jul 24 2014

MATHEMATICA

a057643[n_Integer] := Apply[LCM, Map[# + 1 &, Divisors[n]]]; Table[a057643[n], {n, 10000}] (* Michael De Vlieger, Jul 19 2014 *)

PROG

(PARI) a(n)=lcm(apply(d->d+1, divisors(n))) \\ Charles R Greathouse IV, Feb 14 2013

CROSSREFS

Cf. A119250.

Cf. A020696 (product instead of LCM).

Sequence in context: A226532 A006233 A164020 * A073039 A322792 A253588

Adjacent sequences:  A057640 A057641 A057642 * A057644 A057645 A057646

KEYWORD

nonn

AUTHOR

Leroy Quet, Oct 11 2000

STATUS

approved

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Last modified March 21 20:21 EDT 2019. Contains 321382 sequences. (Running on oeis4.)