reserve c, c1, c2, d, d1, d2, e, y for Real,
  k, n, m, N, n1, N0, N1, N2, N3, M for Element of NAT,
  x for set;

theorem
  for f being Real_Sequence st (for n being Nat holds f.n = log(2,n!))
 for n holds f.n = Sum(seq_logn, n) by Lm44;
