Here's a sequence I've been playing with; is anything much known about it? For a positive integer n, find n mod p, where p is the largest prime not larger than n. Continue with that result, finding its residue mod its largest prime, etc., until you come down to 0 or 1. For example, 9 mod 7 = 2 and 2 mod 2 = 0, so the ninth element is 0. The sequence begins: 1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1 and seems to have blocks of zeroes embedded between 1s. The sequence of the lengths of the blocks of zeroes begins: 2, 1, 1, 3, 1, 3, 1, 3, 2, 2, 1, 2, 2, 3, 1, 3, 2, 2, 2. For n = 9, there are two changes before the final result (9 to 2 and 2 to 0). The sequence of numbers of changes begins: 0, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1 and seems to be of the form of blocks of repeating numbers. The sequence of the lengths of these blocks begins: 1, 7, 2, 4, 2, 4, 2, 2, 4, 4, 4, 2, 2, 4, 2, 2, 4, 2, 4, 4. None of these four sequences is in OEIS. Is this interesting enough to add to OEIS? Kerry -- lkmitch@gmail.com www.fractalus.com/kerry