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A375624
a(n) is the number of integers of the form d_1 - d_2 + d_3 - d_4 + ... + (-1)^k d_k, where n = d_1 > d_2 > ... > d_k = 1, d_{i+1} divides d_i for 1 <= i <= k-1.
2
1, 1, 1, 1, 1, 2, 1, 2, 2, 2, 1, 5, 1, 2, 3, 4, 1, 6, 1, 5, 3, 2, 1, 10, 2, 2, 4, 5, 1, 9, 1, 8, 3, 2, 3, 14, 1, 2, 3, 12, 1, 10, 1, 5, 8, 2, 1, 20, 2, 6, 3, 5, 1, 16, 3, 12, 3, 2, 1, 22, 1, 2, 8, 16, 3, 10, 1, 5, 3, 9, 1, 30, 1, 2, 8, 5, 3, 10, 1, 26, 8, 2, 1, 26, 3, 2, 3, 12, 1, 29
OFFSET
1,6
LINKS
EXAMPLE
n = 4: 3 = 4 - 1;
n = 6: 4 = 6 - 3 + 1, 5 = 6 - 1;
n = 8: 5 = 8 - 4 + 1, 7 = 8 - 1;
n = 9: 7 = 9 - 3 + 1, 8 = 9 - 1;
n = 10: 6 = 10 - 5 + 1, 9 = 10 - 1.
PROG
(PARI) \\ For the PARI program giving the set of such numbers of each n, see A375626.
CROSSREFS
Cf. A375626.
Sequence in context: A233390 A324114 A011776 * A345182 A297791 A098965
KEYWORD
nonn
AUTHOR
Jianing Song, Aug 21 2024
STATUS
approved