Number of 7-ary heaps on n elements.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =6a(5) =24a(6) =120a(7) =720a(8) =5040a(9) =20160a(10) =120960a(11) =907200a(12) =7983360a(13) =79833600a(14) =889574400a(15) =10897286400a(16) =81729648000a(17) =871782912000