A224282 Number of 3Xn 0..3 arrays with diagonals and rows unimodal and antidiagonals nondecreasing.
64, 1600, 13683, 84132, 442089, 2059793, 8626382, 32788075, 114177368, 367630559, 1103854119, 3114501259, 8312578140, 21108455323, 51251494995, 119493052710, 268514504126, 583406544627, 1229033304669, 2516545359868, 5019124209561
Offset: 1
Keywords
Examples
Some solutions for n=3 ..0..0..0....2..3..1....0..3..1....1..0..0....0..3..0....0..0..0....0..0..0 ..2..0..0....3..1..0....3..2..1....3..3..2....3..2..1....1..1..2....0..3..2 ..0..0..2....2..2..1....2..1..1....3..2..0....3..3..3....3..2..2....3..3..0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Formula
Empirical: a(n) = (1/3629463552000)*n^18 + (1/80654745600)*n^17 + (1123/2092278988800)*n^16 + (37607/2615348736000)*n^15 + (1660537/5230697472000)*n^14 + (58097/11496038400)*n^13 + (870097/11496038400)*n^12 + (18766109/28740096000)*n^11 + (404719067/73156608000)*n^10 + (535345591/14631321600)*n^9 + (24473380931/160944537600)*n^8 + (549661909/449064000)*n^7 + (1232106541/768768000)*n^6 + (74468938879/3736212480)*n^5 + (59979142753/8717829120)*n^4 + (521837272841/9081072000)*n^3 + (1774626948209/5145940800)*n^2 - (140683661/117810)*n + 1114 for n>3
Comments