(Python)
def A203718(n, seed = '1'):
...."""
....Returns the nth term of the sequence.
....Optionally specified seed.
...."""
....i = 0
....term = seed
....next_int = 1
....while i < n:
........b = bin(next_int)[2:]
........if b not in term:
............term += b
............i += 1
........next_int += 1
....return term
.
def A203718_list(stop, start = 0, seed = '1'):
...."""
....Returns a slice of the sequence up to the specified index.
....Seed and starting index optional
...."""
....terms = [seed]
....term = seed
....i = 0
....next_int = 1
....while i < stop:
........b = bin(next_int)[2:]
........if b not in term:
............term += b
............if start <= i:
................terms.append(term)
............i += 1
........next_int += 1
....return terms
