A224378 Number of 6Xn 0..2 arrays with rows unimodal and antidiagonals nondecreasing.
729, 69984, 1126072, 8297747, 42132769, 174854516, 644368221, 2212959866, 7296488462, 23473954511, 74124038709, 229565868000, 694675751863, 2045339262040, 5840640774160, 16145608364197, 43177424328109
Offset: 1
Keywords
Examples
Some solutions for n=3 ..0..0..1....0..0..0....0..0..0....0..0..0....0..0..0....0..0..1....0..0..0 ..0..1..0....0..0..2....1..1..0....1..0..0....1..0..0....0..1..0....0..0..0 ..2..2..0....0..2..0....1..0..0....0..2..1....2..2..2....2..2..0....2..1..0 ..2..0..0....2..0..0....2..0..0....2..2..1....2..2..0....2..0..0....1..1..2 ..2..1..1....1..0..0....0..2..2....2..2..1....2..2..0....1..0..0....1..2..0 ..2..1..0....0..1..0....2..2..0....2..2..1....2..2..2....2..1..0....2..1..0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Formula
Empirical: a(n) = (1/35608838483312640000)*n^24 + (1/228261785149440000)*n^23 + (2993/8515157028618240000)*n^22 + (1189/64508765368320000)*n^21 + (565139/810967336058880000)*n^20 + (50213/2502985605120000)*n^19 + (102275011/224083079700480000)*n^18 + (630450937/74694359900160000)*n^17 + (6860509793/52725430517760000)*n^16 + (7572768857/4393785876480000)*n^15 + (1975549547/96566722560000)*n^14 + (5979889787/26153487360000)*n^13 + (129750858133763/52725430517760000)*n^12 + (8852225741519/337983528960000)*n^11 + (1757155928198569/6590678814720000)*n^10 + (11208897154284701/4393785876480000)*n^9 + (15905213251807771/762187345920000)*n^8 + (60693804091491173/444609285120000)*n^7 + (56813409423945822743/88699552381440000)*n^6 + (45278410760324474101/29566517460480000)*n^5 - (4851359450955021973/4927752910080000)*n^4 - (59510428654061699/5133075948000)*n^3 + (926682017129053/38440617600)*n^2 + (89190882279703/5354228880)*n - 49724 for n>4
Comments