A201380 - OEIS

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A201380

Number of nX4 0..1 arrays with rows and columns lexicographically nondecreasing and the instance counts of every value within one of each other

1, 7, 27, 121, 483, 1751, 5694, 16870, 46014, 116842, 278837, 630353, 1358517, 2806843, 5584567, 10741640, 20039166, 36362252, 64333159, 111214759, 188207532, 312302096, 508868575, 815256003, 1285706310, 1998034336, 3062559792

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

Column 4 of A201384

LINKS

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

FORMULA

Empirical: a(n) = 4*a(n-1) +a(n-2) -20*a(n-3) +4*a(n-4) +52*a(n-5) +6*a(n-6) -112*a(n-7) -64*a(n-8) +196*a(n-9) +174*a(n-10) -228*a(n-11) -325*a(n-12) +148*a(n-13) +457*a(n-14) -457*a(n-16) -148*a(n-17) +325*a(n-18) +228*a(n-19) -174*a(n-20) -196*a(n-21) +64*a(n-22) +112*a(n-23) -6*a(n-24) -52*a(n-25) -4*a(n-26) +20*a(n-27) -a(n-28) -4*a(n-29) +a(n-30)

EXAMPLE

Some solutions for n=9

..0..0..0..1....0..0..0..1....0..0..0..1....0..0..0..0....0..0..0..0

..0..0..1..1....0..0..0..1....0..0..1..1....0..0..0..1....0..0..1..1

..0..1..1..0....0..0..1..0....0..0..1..1....0..1..1..0....0..1..0..0

..0..1..1..0....0..1..0..1....0..0..1..1....0..1..1..0....0..1..0..1

..1..0..0..0....0..1..0..1....0..1..0..1....0..1..1..0....0..1..1..0

..1..0..0..1....0..1..0..1....0..1..1..0....0..1..1..1....0..1..1..1

..1..1..0..0....0..1..0..1....1..0..1..0....1..0..1..1....0..1..1..1

..1..1..0..1....1..1..1..0....1..0..1..0....1..1..0..0....1..0..1..1

..1..1..0..1....1..1..1..1....1..0..1..1....1..1..1..0....1..1..0..0

CROSSREFS