a(n) = (2^n-1)*4^(2*n-1).A163839a(n) = (2^n-1)*4^(2*n-1).Terms a(0) =0a(1) =4a(2) =192a(3) =7168a(4) =245760a(5) =8126464a(6) =264241152a(7) =8522825728a(8) =273804165120External referencesoeis: A163839