Number of elements in the coprime subsets of the integers 1 to n.

Terms

a(0) =0a(1) =1a(2) =4a(3) =12a(4) =20a(5) =52a(6) =60a(7) =148a(8) =196a(9) =300a(10) =332a(11) =780a(12) =828a(13) =1904a(14) =2080a(15) =2348a(16) =2812a(17) =6352a(18) =6608a(19) =14736a(20) =15632a(21) =17456a(22) =18640a(23) =41152a(24) =42432a(25) =60912a(26) =64800a(27) =80928a(28) =85408a(29) =186304