Number of nonempty subsets of {1..n} whose elements have an even root mean square.

Terms

a(0) =0a(1) =1a(2) =1a(3) =2a(4) =2a(5) =3a(6) =3a(7) =4a(8) =8a(9) =11a(10) =13a(11) =26a(12) =46a(13) =81a(14) =169a(15) =284a(16) =482a(17) =857a(18) =1461a(19) =2548a(20) =4370a(21) =7917a(22) =14181a(23) =25648a(24) =47330a(25) =87457a(26) =163291a(27) =302678a(28) =568974a(29) =1064393