Number of subsets of {1,2,...,n} that contain the average of their elements.

Terms

a(0) =1a(1) =2a(2) =4a(3) =6a(4) =10a(5) =16a(6) =26a(7) =42a(8) =72a(9) =124a(10) =218a(11) =390a(12) =706a(13) =1292a(14) =2388a(15) =4436a(16) =8292a(17) =15578a(18) =29376a(19) =55592a(20) =105532a(21) =200858a(22) =383220a(23) =732756a(24) =1403848a(25) =2694404a(26) =5179938a(27) =9973430a(28) =19229826a(29) =37125562