A375890 a(1) = 1; for n > 1, a(n) is the smallest unused positive number such that a(n) is coprime to a(n-1) and (a(n) AND a(n-1)) = min(a(n), a(n-1)), where AND is the binary AND operation.
1, 3, 2, 7, 4, 5, 13, 8, 9, 11, 10, 27, 16, 17, 19, 18, 23, 6, 31, 12, 29, 20, 21, 53, 32, 33, 35, 34, 39, 37, 36, 47, 14, 15, 79, 64, 65, 67, 66, 71, 68, 69, 77, 72, 73, 75, 74, 91, 24, 25, 57, 40, 41, 43, 42, 59, 26, 63, 22, 87, 70, 103, 38, 55, 48, 49, 51, 50, 119, 52, 61, 28, 93, 76, 109, 44
Offset: 1
Examples
a(5) = 4 as 4 is coprime to a(4) = 7 and min(7,4) = 4 and (7 AND 4) = 111_2 AND 100_2 = 100_2 = 4.
Links
- Scott R. Shannon, Table of n, a(n) for n = 1..10000
- Scott R. Shannon, Image of the first 100000 terms. The green line is a(n) = n.
Comments