Non-integers
Besides integer sequences, the OEIS also catalogs sequences of fractions, the digits of transcendental numbers, complex numbers and so on by transforming them into integer sequences. Sequences of rationals are represented by two sequences (named with the keyword 'frac'): the sequence of numerators and the sequence of denominators. For example, the fifth order Farey sequence, is catalogued as the numerator sequence 1, 1, 1, 2, 1, 3, 2, 3, 4 ( A006842) and the denominator sequence 5, 4, 3, 5, 2, 5, 3, 4, 5 ( A006843). Important irrational numbers such as π = 3.1415926535897... are catalogued under representative integer sequences such as decimal expansions (here 3, 1, 4, 1, 5, 9, 2, 6, ... ( A000796)) or continued fraction expansions (here 3, 7, 15, 1, 292, 1, ... ( A001203)).
Read more about this topic: On-Line Encyclopedia Of Integer Sequences