A253326 T(n,k)=Number of (n+1)X(k+1) 0..1 arrays with every 2X2 subblock sum nondecreasing horizontally, vertically and antidiagonally ne-to-sw.
16, 44, 44, 121, 126, 121, 286, 373, 377, 286, 676, 1026, 1217, 848, 676, 1482, 2797, 3787, 2538, 2042, 1482, 3249, 6936, 11506, 7744, 6190, 4218, 3249, 6840, 17197, 31999, 23153, 19312, 11795, 9228, 6840, 14400, 39616, 86922, 66196, 58505, 34660
Offset: 1
Examples
Some solutions for n=4 k=4 ..0..0..0..1..0....0..0..0..0..0....0..0..0..0..1....0..0..0..0..1 ..0..0..0..0..1....0..0..0..1..0....0..0..0..0..0....0..1..0..1..0 ..0..0..1..1..0....1..0..1..0..1....0..0..0..1..0....0..0..0..1..0 ..1..1..0..1..1....1..1..1..1..1....1..0..1..0..1....0..1..1..1..1 ..0..1..1..1..1....1..0..1..0..1....1..1..1..1..1....1..0..1..1..1
Links
- R. H. Hardin, Table of n, a(n) for n = 1..418
Crossrefs
Column 1 and row 1 are A204032
Formula
Empirical for column k:
k=1: a(n) = 4*a(n-1) -18*a(n-3) +17*a(n-4) +22*a(n-5) -36*a(n-6) +20*a(n-8) -8*a(n-9)
k=2: [order 13]
k=3: [same order 13] for n>15
k=4: [same order 13] for n>19
k=5: [same order 13] for n>22
k=6: [same order 13] for n>23
k=7: [same order 13] for n>26
Empirical for row n:
n=1: a(n) = 4*a(n-1) -18*a(n-3) +17*a(n-4) +22*a(n-5) -36*a(n-6) +20*a(n-8) -8*a(n-9)
n=2: [order 21]
n=3: [order 39]
n=4: [order 45]
n=5: [order 63]
n=6: [order 65]
n=7: [order 87]
Comments