Number of defective (binary) heaps on n elements from the set {0,1} with exactly one defect.

Terms

a(0) =0a(1) =0a(2) =1a(3) =2a(4) =6a(5) =11a(6) =20a(7) =32a(8) =60a(9) =100a(10) =162a(11) =255a(12) =427a(13) =692a(14) =1093a(15) =1738a(16) =2800a(17) =4507a(18) =6951a(19) =11032a(20) =17224a(21) =27553a(22) =42276a(23) =67639a(24) =103989a(25) =165856a(26) =251312a(27) =401236a(28) =608112a(29) =968380