Number of subsets of the first n numbers having a common divisor greater than 1.

Terms

a(0) =0a(1) =1a(2) =2a(3) =4a(4) =5a(5) =10a(6) =11a(7) =19a(8) =23a(9) =40a(10) =41a(11) =79a(12) =80a(13) =145a(14) =164a(15) =292a(16) =293a(17) =577a(18) =578a(19) =1096a(20) =1163a(21) =2188a(22) =2189a(23) =4357a(24) =4373a(25) =8470a(26) =8726a(27) =16924a(28) =16925a(29) =33832