A085684 Triangle read by rows: T(n,k), n >= 0, 0 <= k <= n, is size of maximal 1-transposition-correcting code formed using binary vectors of length n and weight k.

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 1, 1, 2, 3, 3, 2, 1, 1, 2, 4, 6, 4, 2, 1, 1, 3, 6, 9, 9, 6, 3, 1, 1, 3, 7, 13, 15, 13, 7, 3, 1, 1, 3, 9, 18, 24, 24, 18, 9, 3, 1, 1, 4, 11, 24, 37, 42, 37, 24, 11, 4, 1

Offset: 0

Author

N. J. A. Sloane, Jul 17 2003

Keywords

• nonn
• tabl

Examples

			Triangle begins
1
1 1
1 1 1
1 1 1 1
1 2 2 2 1
1 2 3 3 2 1
1 2 4 6 4 2 1
		

Links

• José Manuel Gómez Soto, Jesús Leaños, Luis Manuel Ríos-Castro, Luis Manuel Rivera, On an error-correcting code problem, arXiv:1711.03682 [math.CO], 2017.
• N. J. A. Sloane, Challenge Problems: Independent Sets in Graphs

Crossrefs

Column k=1 is floor(n/3), column k=2 is A085680, row sums are A057608.