a(n) = n^n - 1.A048861a(n) = n^n - 1.Terms a(0) =0a(1) =3a(2) =26a(3) =255a(4) =3124a(5) =46655a(6) =823542a(7) =16777215a(8) =387420488a(9) =9999999999a(10) =285311670610External referencesoeis: A048861