The Riddle In The Middle

Whats next in this sequence:

1,2,3,4,5,6,7,...

No its not 8. Its 9.

See, the function that created this sequence is:

f(n) = n + floor(n/8)

Wisdom Of The Day:

"When something looks so easy,
suspicion would be the best first thing to do."

Any extra wisdoms you can think of?