A074747 Largest difference between consecutive anti-divisors of n (ordered by size).

0, 0, 0, 0, 1, 0, 2, 2, 4, 3, 4, 3, 4, 5, 4, 8, 4, 5, 10, 5, 8, 6, 6, 9, 7, 13, 7, 8, 16, 8, 12, 8, 9, 19, 9, 16, 10, 10, 15, 11, 18, 11, 12, 21, 12, 18, 14, 14, 19, 13, 28, 14, 14, 24, 15, 21, 17, 16, 22, 16, 30, 20, 17, 40, 17, 25, 18, 18, 40, 19, 34, 19, 20, 28, 20, 34, 20, 21, 50, 21

Offset

1,7

Comments

For 2<=k<n and k even, k is an anti-divisor of n iff n==k/2 (mod k) for 2<=k<n and k odd, k is an anti-divisor of n iff either n==(k-1)/2 (mod k) or n==(k+1)/2 (mod k) when there are fewer than 2 anti-divisors of n, a(n) = 0. - Weston Markham (weston.markham(AT)gmail.com), May 22 2005

See A066272 for definition of anti-divisor.

Links

Table of n, a(n) for n=1..80.

Example

For n=13, anti-divisors={2,3,5,9}; differences={1,2,4}; a(13) = largest difference = 4.

Crossrefs

Cf. A066272.

Sequence in context: A078317 A105016 A377369 * A128248 A347659 A224901

Adjacent sequences: A074744 A074745 A074746 * A074748 A074749 A074750

Keyword

nonn

Author

Jason Earls, Sep 06 2002

Extensions

More terms from Weston Markham (weston.markham(AT)gmail.com), May 22 2005

Status

approved