Modulo 2 binomial transform of 3^n.

Terms

a(0) =1a(1) =4a(2) =10a(3) =40a(4) =82a(5) =328a(6) =820a(7) =3280a(8) =6562a(9) =26248a(10) =65620a(11) =262480a(12) =538084a(13) =2152336a(14) =5380840a(15) =21523360a(16) =43046722a(17) =172186888a(18) =430467220a(19) =1721868880a(20) =3529831204a(21) =14119324816a(22) =35298312040a(23) =141193248160a(24) =282472589764