OFFSET
1,4
LINKS
Dongsu Kim and Zhicong Lin, Refined restricted inversion sequences, arXiv:1706.07208 [math.CO], 2017-2020.
Toufik Mansour and Mark Shattuck, On a conjecture of Lin and Kim concerning a refinement of Schröder numbers, arXiv:2104.04491 [math.CO], 2021.
EXAMPLE
Triangle begins:
1;
1, 1;
2, 2, 2;
4, 6, 6, 6;
8, 16, 22, 22, 22;
16, 40, 68, 90, 90, 90;
...
PROG
(PARI)
T(n, k) = if (k>=1, if (n<=2, 1, if (k<=n-2, T(n, k-1)+2*T(n-1, k)-T(n-1, k-1), T(n, n-2))));
tabl(nn) = {for (n=1, nn, for (k=1, n, print1(T(n, k), ", "); ); print; ); }
CROSSREFS
KEYWORD
AUTHOR
Michel Marcus, Apr 12 2021
STATUS
approved