A223671 Number of 4Xn 0..1 arrays with rows, diagonals and antidiagonals unimodal.
16, 256, 1723, 6454, 18980, 49561, 119150, 267643, 567197, 1142224, 2198273, 4062420, 7238132, 12477929, 20877528, 33995513, 54002935, 83867606, 127578211, 190413722, 279263958, 403007495, 572953490, 803354343, 1111996481, 1520876908
Offset: 1
Keywords
Examples
Some solutions for n=4 ..1..0..0..0....0..1..1..0....0..0..0..0....0..1..1..1....0..0..0..1 ..0..1..0..0....0..0..0..0....1..1..0..0....0..1..1..0....0..1..1..0 ..0..1..1..1....0..1..0..0....0..0..1..1....1..1..1..0....1..0..0..0 ..1..0..0..0....0..0..1..0....0..0..0..0....0..1..1..0....0..0..1..0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Formula
Empirical: a(n) = (1/112)*n^8 - (19/210)*n^7 + (59/45)*n^6 - (61/120)*n^5 - (8789/144)*n^4 + (99083/120)*n^3 - (10598579/2520)*n^2 + (1548737/140)*n - 11539 for n>6
Comments