In mathematics, the Mian–Chowla sequence is an integer sequence defined recursively in the following way.
The sequence starts with Then for
is the smallest integer such that every pairwise sum is distinct, for all
The next term in the sequence,
, is 2 since the pairwise sums then are 2, 3 and 4, i.e., they are distinct.
can't be 3 because there would be the non-distinct pairwise sums 1 + 3 = 2 + 2 = 4.
The sequence thus begins If we define
, the resulting sequence is the same except each term is one less (that is, 0, 1, 3, 7, 12, 20, 30, 44, 65, 80, 96, ... OEIS: A025582).
The sequence was invented by Abdul Majid Mian and Sarvadaman Chowla.