OFFSET
1,2
COMMENTS
See Comments section in A245027.
The following 36 triangular numbers belong to this sequence: 1, 3, 6, 10, 15, 21, 28, 36, 45, 78, 91, 105, 120, 171, 190, 210, 630, 666, 703, 741, 780, 1596, 1830, 4095, 4560, 5460, 6216, 16653, 33670, 46360, 103740, 115440, 221445, 274170, 365085, 392303547090.
The following terms of A001082 (without 1, 21 and 120, which appear in the previous list) are in sequence: 5, 8, 16, 40, 56, 65, 133, 208, 280, 456, 481, 560, 936, 1008, 1281, 1365, 1680, 1776, 1976, 4880, 5985, 10920, 11285, 44408, 47880, 590520, 658008, 731120, 973560, 1046142792240.
Also, 4/5 of the members are divisible by 3 and 2/3 of them are even.
LINKS
EXAMPLE
3138428376720 = 2^4 * 3^2 * 5 * 7 * 13 * 19 * 37 * 61 * 1117.
MATHEMATICA
Divisors[11^12 - 1]
PROG
(PARI) divisors(11^12-1)
(Sage) divisors(11^12-1)
(Magma) Divisors(11^12-1);
(Maxima) divisors(11^12-1);
CROSSREFS
KEYWORD
nonn,fini,full
AUTHOR
Bruno Berselli, Jul 10 2014
STATUS
approved