0,2

Sequence is interesting because the initial terms seem to have many small factors.

Table of n, a(n) for n=0..27.

a(n) = 2 cos(pi (n+1)/3) binomial(n+7,7). Note that 2 cos(pi (n+1)/3) is always 1, -1, 2, or -2, so this formula explains the small factors. - Dean Hickerson, Feb 06 2006

Sequence in context: A032554 A097255 A115693 * A043932 A064015 A044576

Adjacent sequences: A112400 A112401 A112402 * A112404 A112405 A112406

sign

Creighton Dement, Dec 06 2005

approved