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

Author

Reinhard Zumkeller, Apr 11 2011

Keywords

• nonn
• base

Examples

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

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
• Index entries for sequences related to lcm's

Crossrefs

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

Cf. A000040, A004087, A002385.

Programs

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

Formula

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

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