Number of distinct residues x^4 (mod 2^n), x=0..2^n-1.

Terms

a(0) =1a(1) =2a(2) =2a(3) =2a(4) =2a(5) =4a(6) =6a(7) =10a(8) =18a(9) =36a(10) =70a(11) =138a(12) =274a(13) =548a(14) =1094a(15) =2186a(16) =4370a(17) =8740a(18) =17478a(19) =34954a(20) =69906a(21) =139812a(22) =279622a(23) =559242a(24) =1118482a(25) =2236964a(26) =4473926