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A239661 Divisors of 1089. 0
1, 3, 9, 11, 33, 99, 121, 363, 1089 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Divisors of 33^2.

The sum of divisors of 1089 is equal to 1729, the Hardy-Ramanujan number: A000203(1089) = A001235(1) = 1729.

The aliquot divisors of 1089 are also the powers of 3 written in base 26, see A004668.

Also 1089 is widely used in magic tricks because it can be produced from any two three-digit numbers (see Links section).

LINKS

Table of n, a(n) for n=1..9.

Wikipedia, 1089 (number)

EXAMPLE

Sigma(1089) = 1 + 3 + 9 + 11 + 33 + 99 + 121 + 363 + 1089 = 1729.

MATHEMATICA

Divisors[1089] (* Wesley Ivan Hurt, Jun 13 2014 *)

PROG

(PARI) divisors(1089) \\ Michel Marcus, Jun 14 2014

CROSSREFS

Cf. A000203, A001235, A004668.

Sequence in context: A027894 A249647 A004668 * A106305 A135365 A088877

Adjacent sequences:  A239658 A239659 A239660 * A239662 A239663 A239664

KEYWORD

nonn,easy,fini,full

AUTHOR

Omar E. Pol, Jun 10 2014

STATUS

approved

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Last modified October 22 08:00 EDT 2019. Contains 328315 sequences. (Running on oeis4.)