Binary XOR of (3^k - 1)/2 as k varies from 1 to n.

Terms

a(0) =1a(1) =5a(2) =8a(3) =32a(4) =89a(5) =309a(6) =1392a(7) =2464a(8) =12241a(9) =23685a(10) =66936a(11) =329856a(12) =598377a(13) =2972885a(14) =4204000a(15) =17321536a(16) =47254689a(17) =156943365a(18) =737779176a(19) =1276350496a(20) =6369950073a(21) =12290868597a(22) =35051319632a(23) =175157734688a(24) =319624706161