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, 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
Keywords
Examples
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
Links
- Amiram Eldar, Table of n, a(n) for n = 1..150