Bakare, G. N.,Makanjuola, S. O.2020-02-202020-02-202018-11Bakare, G. N., and Makanjuola, S. O. (2018)2616-1303http://hdl.handle.net/123456789/3799Let Cn be the charts on Xn = {1,2,...,n} be the alternating semigroups, OAnc be the subsemigroups of order preserving alternating semigroups and N(S) be the set of nilpotents element of a semigroups OAnc . Let G(n;p,m) = | {aeS : h(a) = p^f(a) = m }| ,G(n;m) = | {aeS : f(a) = m }| and G(p; m) = | {aeS : h(a) = p }| . In this paper, some combinatorial properties of OAnc for two parameters G(n; p) were discuss and their nilpotent elements were also investigated.enSemigroups,Chart,Nilpotent elements.Alternating Semigroup,Order-Preserving Alternating SemigroupArticle