a(n) = 4 * A051189(n).A153511a(n) = 4 * A051189(n).Terms a(0) =4a(1) =32a(2) =512a(3) =12288a(4) =393216a(5) =15728640a(6) =754974720a(7) =42278584320External referencesoeis: A153511