A220156 Number of 4Xn arrays of the minimum value of corresponding elements and their horizontal or diagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and nonincreasing columns, 0..2 4Xn array.
15, 52, 242, 1174, 4559, 16110, 53947, 173732, 539903, 1620236, 4698464, 13180052, 35802185, 94277039, 240952485, 598495844, 1446788180, 3408685943, 7838407335, 17616947657, 38749982170, 83520468048, 176604065342, 366743870453
Offset: 1
Keywords
Examples
Some solutions for n=3 ..0..0..0....1..0..0....1..0..0....0..0..0....0..0..0....1..0..0....1..1..1 ..1..0..0....1..0..0....1..0..0....1..0..0....0..0..0....2..0..0....1..0..1 ..1..1..1....2..0..0....2..0..0....1..1..2....1..1..0....2..1..1....1..0..0 ..2..2..1....2..0..0....2..1..1....1..1..1....1..1..1....2..2..2....1..1..1
Links
- R. H. Hardin, Table of n, a(n) for n = 1..121
Formula
Empirical: a(n) = (1/969450627708186624000000)*n^25 - (1/4562120600979701760000)*n^24 + (2027/77556050216654929920000)*n^23 - (331/177473799122780160000)*n^22 + (5539/80669908692172800000)*n^21 + (5921/3128016867655680000)*n^20 - (18577907/38318206628782080000)*n^19 + (18754471/474528874659840000)*n^18 - (41570691557/20167477173043200000)*n^17 + (5382522617/73004442255360000)*n^16 - (17042278220257/10439635242516480000)*n^15 + (9851672121271/1491376463216640000)*n^14 + (58162480943607049/52198176212582400000)*n^13 - (135094442095532831/2609908810629120000)*n^12 + (635574550376155319/474528874659840000)*n^11 - (1347751237421517133/59316109332480000)*n^10 + (296554709147396003149/1260467323315200000)*n^9 - (2610520959289132961/4236864952320000)*n^8 - (80984035976231237377421/3193183885731840000)*n^7 + (22349422485612993076363/44349776190720000)*n^6 - (7737663764129137016063569/1524523556556000000)*n^5 + (3378006014145622282711/109727291520000)*n^4 - (83444980373091022514603/820211504112000)*n^3 + (294465474881972180993/4365271310400)*n^2 + (987245448964903837/1487285800)*n - 1630947583 for n>18
Comments