Unless a greater proportion is required by this chapter or by the certificate of incorporation or by a by-law adopted by the members, a majority of the entire board shall constitute a quorum for the transaction of business or of any specified item of business, except that the certificate of incorporation or the by-laws may fix the quorum at less than a majority of the entire board, provided that in the case of a board of fifteen members or less the quorum shall be at least one-third of the entire number of members and in the case of a board of more than fifteen members the quorum shall be at least five members plus one additional member for every ten members (or fraction thereof) in excess of fifteen.
N.Y. Not-For-Profit Corp. Law § 707