A250386 Number of length n+3 0..7 arrays with no four consecutive terms having the maximum of any two terms equal to the minimum of the remaining two terms

3192, 21168, 141344, 944272, 6308960, 42158796, 281731072, 1882722300, 12581692558, 84080003928, 561883915314, 3754919165700, 25093116937722, 167690571894812, 1120631136647428, 7488877503016204, 50046161038946360

Offset

1,1

Comments

Column 7 of A250387

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 4*a(n-1) +22*a(n-2) -46*a(n-3) +133*a(n-4) +616*a(n-5) -4201*a(n-6) -3646*a(n-7) +21341*a(n-8) -66632*a(n-9) -24894*a(n-10) +839903*a(n-11) -475399*a(n-12) -2431863*a(n-13) +8820646*a(n-14) -6093429*a(n-15) -52029372*a(n-16) +78800953*a(n-17) +60427131*a(n-18) -440849842*a(n-19) +475646104*a(n-20) +1126920187*a(n-21) -2461056791*a(n-22) +868584593*a(n-23) +6052348452*a(n-24) -10666379285*a(n-25) -2036000169*a(n-26) +21839852091*a(n-27) -28252527846*a(n-28) -11493718820*a(n-29) +60075332084*a(n-30) -34089181484*a(n-31) -34480114740*a(n-32) +75274463592*a(n-33) -15832208844*a(n-34) -47658620844*a(n-35) +21572342568*a(n-36) -12371339232*a(n-37) -5079648672*a(n-38) +22260620880*a(n-39) -916920000*a(n-40) -3811095360*a(n-41) +639187200*a(n-42) -1581638400*a(n-43) -93312000*a(n-44) +373248000*a(n-45)

Example

Some solutions for n=3
..5....3....6....5....0....1....1....2....6....2....2....5....6....6....2....2
..3....5....3....2....1....7....3....0....2....3....7....0....2....2....7....7
..1....7....0....2....4....3....2....5....3....4....3....0....5....3....1....7
..5....6....7....7....0....6....6....1....5....7....4....2....7....7....7....5
..5....7....0....5....3....5....1....4....6....5....6....3....1....7....4....2
..1....3....7....4....2....1....1....6....3....6....6....4....4....6....1....6

Crossrefs

Sequence in context: A252367 A345589 A345847 * A069401 A225056 A306197

Adjacent sequences: A250383 A250384 A250385 * A250387 A250388 A250389

Keyword

nonn

Author

R. H. Hardin, Nov 20 2014

Status

approved