A322359 Least common multiple of product (p-1) and product (p+1), where p ranges over distinct prime divisors of n.

1, 3, 4, 3, 12, 12, 24, 3, 4, 36, 60, 12, 84, 24, 24, 3, 144, 12, 180, 36, 96, 180, 264, 12, 12, 84, 4, 24, 420, 72, 480, 3, 240, 432, 48, 12, 684, 180, 168, 36, 840, 96, 924, 180, 24, 792, 1104, 12, 24, 36, 288, 84, 1404, 12, 360, 24, 720, 1260, 1740, 72, 1860, 480, 96, 3, 336, 720, 2244, 432, 1056, 144, 2520, 12

Offset

1,2

Links

Antti Karttunen, Table of n, a(n) for n = 1..16384

Index entries for sequences related to lcm's

Formula

a(n) = lcm(A048250(n), A173557(n)).

a(n) = A322360(n)/A066086(n).

Mathematica

a[n_] := If[n == 1, 1, Module[{f=FactorInteger[n]}, LCM[Times@@((#-1)& @@@ f), Times@@((#+1)& @@@ f)]]]; Array[a, 100] (* Amiram Eldar, Dec 05 2018 *)

Prog

(PARI)
A048250(n) = factorback(apply(p -> p+1, factor(n)[, 1]));
A173557(n) = factorback(apply(p -> p-1, factor(n)[, 1]));
A322359(n) = lcm(A048250(n), A173557(n));

Crossrefs

Cf. A048250, A066086, A173557, A322360.

Sequence in context: A051508 A281230 A323977 * A172990 A084252 A342161

Adjacent sequences: A322356 A322357 A322358 * A322360 A322361 A322362

Keyword

nonn

Author

Antti Karttunen, Dec 04 2018

Status

approved