A250385 Number of length n+3 0..6 arrays with no four consecutive terms having the maximum of any two terms equal to the minimum of the remaining two terms.

1806, 10206, 58114, 331128, 1886948, 10755158, 61304844, 349446100, 1991900312, 11354195442, 64721045790, 368922293032, 2102927637802, 11987090744306, 68328717101584, 389486802126274, 2220149536957226, 12655278559105378

Offset

1,1

Comments

Column 6 of A250387

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +15*a(n-2) -21*a(n-3) +139*a(n-4) +312*a(n-5) -1832*a(n-6) -664*a(n-7) +2628*a(n-8) -29790*a(n-9) +11956*a(n-10) +169567*a(n-11) -139200*a(n-12) +40466*a(n-13) +1341516*a(n-14) -2063152*a(n-15) -3461814*a(n-16) +7379053*a(n-17) -5556788*a(n-18) -18198303*a(n-19) +33327062*a(n-20) +4535061*a(n-21) -47630248*a(n-22) +81165409*a(n-23) +7944117*a(n-24) -129618610*a(n-25) +92674078*a(n-26) +25970247*a(n-27) -160762841*a(n-28) +54830754*a(n-29) +77231443*a(n-30) -20533632*a(n-31) +32684440*a(n-32) -4271920*a(n-33) -28113280*a(n-34) +1315200*a(n-35) -748800*a(n-36) +1728000*a(n-38)

Example

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

Crossrefs

Sequence in context: A256027 A196788 A252029 * A345765 A035868 A122477

Adjacent sequences: A250382 A250383 A250384 * A250386 A250387 A250388

Keyword

nonn

Author

R. H. Hardin, Nov 20 2014

Status

approved