A188649 Least common multiple of reversals of divisors of n in decimal representation.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 84, 31, 574, 255, 488, 71, 162, 91, 20, 84, 22, 32, 168, 260, 62, 72, 1148, 92, 510, 13, 11224, 33, 6106, 1855, 2268, 73, 15106, 93, 40, 14, 6888, 34, 44, 4590, 64, 74, 10248, 658, 260, 1065, 3100, 35, 3240, 55, 149240, 6825, 7820, 95, 7140, 16, 26, 252, 11224, 8680, 66, 76, 12212, 96, 152110, 17, 4536, 37, 6862, 251940, 2024204, 77

Offset

1,2

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Index entries for sequences related to lcm's

Formula

a(A000040(n)) = A004087(n);

a(A002385(n)) = A002385(n), see A188650 for all fixed points.

Example

Divisors(42) = {1,2,3,6,7,14,21,42}, therefore a(42) = lcm(1,2,3,6,7,41,12,24) = 6888.

Prog

(Haskell)
a188649 n = foldl lcm 1 $ map a004086 $ filter ((== 0) . mod n) [1..n]
(PARI) a(n) = lcm(apply(x->fromdigits(Vecrev(digits(x))), divisors(n))); \\ Michel Marcus, Mar 13 2018
(Python)
from math import lcm
from sympy import divisors
def a(n): return lcm(*(int(str(d)[::-1]) for d in divisors(n)))
print([a(n) for n in range(1, 78)]) # Michael S. Branicky, Aug 14 2022

Crossrefs

Cf. A003990 (LCM), A027750 (divisors), A004086 (reversal), A188650.

Cf. A000040, A004087, A002385.

Sequence in context: A062279 A088599 A004862 * A068634 A049872 A239218

Adjacent sequences: A188646 A188647 A188648 * A188650 A188651 A188652

Keyword

nonn,base

Author

Reinhard Zumkeller, Apr 11 2011

Status

approved