A224175 Number of 4 X n 0..3 arrays with rows, diagonals and antidiagonals unimodal and columns nondecreasing.
35, 1225, 22988, 272130, 2335459, 15925611, 91494280, 459681672, 2071283343, 8522430293, 32452346859, 115542470121, 387735671674, 1234254138386, 3746228897820, 10888055937498, 30409729685443, 81862695894551, 212957974479177, 536558013233411, 1311963232523951
Offset: 1
Keywords
Examples
Some solutions for n=3: ..0..0..1....0..3..1....1..2..0....0..1..1....0..1..1....0..1..1....0..1..0 ..0..2..3....3..3..1....1..3..3....0..2..2....0..1..3....1..2..1....3..1..1 ..1..2..3....3..3..1....3..3..3....0..2..2....0..3..3....1..2..2....3..2..1 ..2..2..3....3..3..3....3..3..3....3..2..2....2..3..3....3..3..3....3..2..2
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Row 4 of A224173.
Formula
Empirical: a(n) = (1/2906843957821440000)*n^24 + (1/80745665495040000)*n^23 + (40627/53523844179886080000)*n^22 + (149/6436248698880000)*n^21 + (6593077/9731608032706560000)*n^20 + (3395111/221172909834240000)*n^19 + (6648319/21341245685760000)*n^18 + (58653979/10670622842880000)*n^17 + (28432949/331085905920000)*n^16 + (2936797909/2510734786560000)*n^15 + (18556527629/1369491701760000)*n^14 + (39701629159/289700167680000)*n^13 + (122790999059713/110472330608640000)*n^12 + (19552381958779/2510734786560000)*n^11 + (343066282192637/7532204359680000)*n^10 + (2966503457023/14265538560000)*n^9 + (24242241250827793/32011868528640000)*n^8 + (16514299013828449/8002967132160000)*n^7 + (364205524025441321/152056375511040000)*n^6 + (32838681788587261/2111894104320000)*n^5 - (148032441802153/14768490240000)*n^4 - (1586985136748719/5866372512000)*n^3 + (228836377537124017/148419224553600)*n^2 - (1300791949339/411863760)*n + 2639 for n>2.
Extensions
Name corrected by Andrew Howroyd, Mar 18 2025