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A343737
Highly composite 7-rough numbers: numbers that are not divisible by any prime smaller than 7 and whose number of divisors reaches a record.
1
1, 7, 49, 77, 539, 1001, 5929, 7007, 17017, 77077, 119119, 323323, 1310309, 2263261, 7436429, 24895871, 52055003, 215656441, 572605033, 1509595087, 6685349671, 16605545957, 46797447697, 215872097441, 247357937827, 514771924667, 1731505564789, 6692035020671
OFFSET
1,2
LINKS
EXAMPLE
n a(n) prime factorization number of divisors
-- ------ ---------------------- ------------------
1 1 - 1
2 7 7 2
3 49 7^2 3
4 77 7 * 11 4
5 539 7^2 * 11 6
6 1001 7 * 11 * 13 8
7 5929 7^2 * 11^2 9
8 7007 7^2 * 11 * 13 12
9 17017 7 * 11 * 13 * 17 16
10 77077 7^2 * 11^2 * 13 18
11 119119 7^2 * 11 * 13 * 17 24
CROSSREFS
KEYWORD
nonn
AUTHOR
Jon E. Schoenfield, Jun 27 2021
STATUS
approved