a(n) = (31^n - 1)/30.A218734a(n) = (31^n - 1)/30.Terms a(0) =0a(1) =1a(2) =32a(3) =993a(4) =30784a(5) =954305a(6) =29583456a(7) =917087137a(8) =28429701248a(9) =881320738689External referencesoeis: A218734