

A250156


Number of length 2+6 0..n arrays with every seven consecutive terms having the maximum of some two terms equal to the minimum of the remaining five terms.


1



193, 3450, 26710, 129595, 468231, 1382188, 3522460, 8028405, 16761565, 32604286, 59831058, 104560495, 175295875, 283562160, 444647416, 678456553, 1010485305, 1472922370, 2105887630, 2958814371, 4091983423, 5578217140, 7504741140
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OFFSET

1,1


LINKS

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


FORMULA

Empirical: a(n) = (11/7)*n^7 + 13*n^6 + (67/2)*n^5 + (97/2)*n^4 + (103/2)*n^3 + 34*n^2 + (139/14)*n + 1.
Conjectures from Colin Barker, Nov 12 2018: (Start)
G.f.: x*(193 + 1906*x + 4514*x^2 + 1707*x^3  339*x^4  68*x^5 + 8*x^6  x^7) / (1  x)^8.
a(n) = 8*a(n1)  28*a(n2) + 56*a(n3)  70*a(n4) + 56*a(n5)  28*a(n6) + 8*a(n7)  a(n8) for n>8.
(End)


EXAMPLE

Some solutions for n=4:
..0....3....3....2....3....2....1....1....3....2....0....2....2....3....3....0
..1....1....2....4....3....0....2....3....3....1....2....2....1....2....0....3
..1....0....2....2....2....0....0....0....4....2....0....2....2....0....4....0
..1....2....2....3....2....4....3....3....1....1....1....2....3....2....4....2
..4....1....2....1....3....0....3....1....1....4....0....3....1....0....1....3
..3....2....4....2....0....0....0....0....1....1....4....2....0....0....1....0
..4....3....0....2....3....4....0....0....3....1....0....1....1....2....1....0
..0....3....4....3....4....2....4....4....2....0....0....2....1....3....3....0


CROSSREFS

Row 2 of A250154.
Sequence in context: A166540 A178265 A201112 * A197112 A120851 A302332
Adjacent sequences: A250153 A250154 A250155 * A250157 A250158 A250159


KEYWORD

nonn


AUTHOR

R. H. Hardin, Nov 13 2014


STATUS

approved



