A245027 Divisors of 7^12 - 1.

1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 13, 15, 16, 18, 19, 20, 24, 25, 26, 30, 32, 36, 38, 39, 40, 43, 45, 48, 50, 52, 57, 60, 65, 72, 75, 76, 78, 80, 86, 90, 95, 96, 100, 104, 114, 117, 120, 129, 130, 144, 150, 152, 156, 160, 171, 172, 180, 181, 190, 195, 200, 208

Offset: 1

Author

Bruno Berselli, Jul 10 2014

Keywords

• nonn
• fini
• full

Comments

Number of divisors of k^12-1 for k = 2..20: 24 (2), 80 (3), 96 (4), 240 (5), 128 (6), 864 (7), 512 (8), 384 (9), 256 (10), 1920 (11), 256 (12), 960 (13), 384 (14), 448 (15), 768 (16), 1792 (17), 768 (18), 3840 (19), 384 (20).

The following triangular numbers belong to this sequence: 1, 3, 6, 10, 15, 36, 45, 78, 120, 171, 190, 300, 325, 741, 780, 2080, 2850, 4560, 8385, 14706, 16290, 5915080, 1730160900.

Examples

			13841287200 = 2^5 * 3^2 * 5^2 * 13 * 19 * 43 * 181.
		

Links

• Bruno Berselli, Table of n, a(n) for n = 1..864
• Index entries for sequences related to divisors of numbers

Crossrefs

Cf. Divisors of k^12-1: A003524 (k=2); A003532 (k=4); A003543 (k=8), A027902 (k=9), A027897 (k=10), A245028 (k=11).

Programs

Magma

Divisors(7^12-1);

Mathematica

Divisors[7^12 - 1]

Maxima

divisors(7^12-1);

PARI

divisors(7^12-1)

Sage

divisors(7^12-1)