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

Terms

a(0) =1a(1) =2a(2) =2a(3) =6a(4) =18a(5) =70a(6) =274a(7) =1094a(8) =4370a(9) =17478a(10) =69906a(11) =279622a(12) =1118482a(13) =4473926a(14) =17895698a(15) =71582790a(16) =286331154a(17) =1145324614a(18) =4581298450a(19) =18325193798a(20) =73300775186a(21) =293203100742