a(n) = (-1)^n * Sum_{k=0..n} (-1)^k*2^(2^k).A325912a(n) = (-1)^n * Sum_{k=0..n} (-1)^k*2^(2^k).Terms a(0) =2a(1) =2a(2) =14a(3) =242a(4) =65294a(5) =4294902002External referencesoeis: A325912