Number of subsets of {1..n} whose root mean square is an integer.

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =5a(5) =6a(6) =9a(7) =10a(8) =15a(9) =20a(10) =29a(11) =52a(12) =87a(13) =166a(14) =311a(15) =538a(16) =943a(17) =1682a(18) =2915a(19) =5054a(20) =8905a(21) =15904a(22) =28533a(23) =51826a(24) =95191a(25) =175402a(26) =325777a(27) =607542a(28) =1134191a(29) =2128922