OFFSET
1,3
LINKS
Robert Gill, The number of elements in a generalized partition semilattice, Discrete mathematics 186.1-3 (1998): 125-134. See Example 2. (Example 1, read by antidiagonals downwards, is A257565.)
EXAMPLE
The first few antidiagonals are:
1,
1,2,
1,4,5,
1,6,23,15,
1,8,53,173,52,
1,10,95,619,1602,203,
...
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
N. J. A. Sloane, Oct 26 2018
EXTENSIONS
More terms from Ilya Gutkovskiy, Oct 29 2018
STATUS
approved