A219941 Number of 3Xn 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..3 3Xn array

20, 76, 368, 2070, 8523, 30558, 100761, 313108, 921941, 2585664, 6949146, 18004266, 45195087, 110356035, 262913226, 612588113, 1398558018, 3133356168, 6897689403, 14935630967, 31839486936, 66877133838, 138505092333, 283012794327

Offset

1,1

Comments

Row 3 of A219939

Links

R. H. Hardin, Table of n, a(n) for n = 1..143

Formula

Empirical: a(n) = (1/403291461126605635584000000)*n^26 + (1/4431774298094567424000000)*n^25 - (1/41363226782215962624000)*n^24 + (197/620448401733239439360000)*n^23 + (1217/8174550747473510400000)*n^22 - (256279/24523652242420531200000)*n^21 + (65279/408727537373675520000)*n^20 + (1856273/87584472294359040000)*n^19 - (653349821/430239513024921600000)*n^18 + (54055377587/1290718539074764800000)*n^17 + (2320366871/27839027313377280000)*n^16 - (3717812638987/83517081940131840000)*n^15 + (5484808764935099/3619073550739046400000)*n^14 - (2496111855647623/119310117057331200000)*n^13 - (72022776713071/632705166213120000)*n^12 + (37557787492220189/3796230997278720000)*n^11 - (2181011993923982069/13444984782028800000)*n^10 + (27307415379539594171/80669908692172800000)*n^9 + (1343328329294561945371/38318206628782080000)*n^8 - (2841881108865735917063/3649353012264960000)*n^7 + (1799819148808436831247773/195139015239168000000)*n^6 - (3401216027548345002782833/48784753809792000000)*n^5 + (46648398935022032997047/138524609583360000)*n^4 - (7212118970409085627577/7792009289064000)*n^3 + (9943478169830685757/12528895579200)*n^2 + (4275677919744929/1912224600)*n - 4212297 for n>13

Example

Some solutions for n=3
..2..0..1....1..1..2....2..2..2....1..1..1....3..0..0....2..2..2....2..0..2
..3..0..0....1..0..1....3..3..2....1..1..1....3..3..3....2..2..2....3..0..0
..3..0..0....2..0..0....3..3..3....2..1..1....3..3..3....3..2..2....3..0..0

Crossrefs

Sequence in context: A320484 A066126 A228025 * A266133 A083127 A211613

Adjacent sequences: A219938 A219939 A219940 * A219942 A219943 A219944

Keyword

nonn

Author

R. H. Hardin Dec 01 2012

Status

approved