a(1) = 1, for n >= 2: a(n) = n^(a(n-1)) - 1.A175982a(1) = 1, for n >= 2: a(n) = n^(a(n-1)) - 1.Terms a(0) =1a(1) =1a(2) =2a(3) =15a(4) =30517578124External referencesoeis: A175982