a(n) = (41^n - 1)/40.A218744a(n) = (41^n - 1)/40.Terms a(0) =0a(1) =1a(2) =42a(3) =1723a(4) =70644a(5) =2896405a(6) =118752606a(7) =4868856847a(8) =199623130728External referencesoeis: A218744