Number of even non-cototients not exceeding 2^n.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =2a(5) =6a(6) =10a(7) =23a(8) =48a(9) =99a(10) =194a(11) =392a(12) =791a(13) =1600a(14) =3290a(15) =6810a(16) =13900a(17) =28269a(18) =57455a(19) =116213a(20) =234237a(21) =470861a(22) =945510a(23) =1897007a(24) =3802257a(25) =7616206a(26) =15244011a(27) =30493702a(28) =60965480a(29) =121838430