OFFSET
1,6
LINKS
FORMULA
a(n) = Sum_{i=1..floor(n/2)} (1 - ceiling(n*i/(n-i)) + floor(n*i/(n-i))).
EXAMPLE
a(6) = 2; The partitions of 6 into 2 parts are (1,5), (2,4) and (3,3). Since 4 | 2*6 = 12 and 3 | 3*6 = 18, we have two such partitions.
MATHEMATICA
Table[Sum[(1 - Ceiling[n*i/(n - i)] + Floor[n*i/(n - i)]), {i, Floor[n/2]}], {n, 100}]
PROG
(PARI) A338021(n) = sum(s=1, n\2, !((s*n)%(n-s))); \\ Antti Karttunen, Dec 12 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Wesley Ivan Hurt, Oct 06 2020
EXTENSIONS
Data section extended up to 105 terms by Antti Karttunen, Dec 12 2021
STATUS
approved