a(n) = n*20^(n-1).A061650a(n) = n*20^(n-1).Terms a(0) =1a(1) =40a(2) =1200a(3) =32000a(4) =800000a(5) =19200000a(6) =448000000a(7) =10240000000a(8) =230400000000External referencesoeis: A061650