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A224645 Number of (n+2)X4 0..1 matrices with each 3X3 subblock having the same population 1
1280, 2688, 5696, 12320, 31232, 80160, 209216, 587424, 1660544, 4729760, 13842944, 40629408, 119599040, 355446048, 1057577216, 3150294560, 9416112512, 28157621280, 84241395776, 252347085984, 756062793344, 2265711086240 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A224651

LINKS

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

FORMULA

Empirical: a(n) = 4*a(n-1) -3*a(n-2) +36*a(n-3) -144*a(n-4) +108*a(n-5) -503*a(n-6) +2012*a(n-7) -1509*a(n-8) +3480*a(n-9) -13920*a(n-10) +10440*a(n-11) -12564*a(n-12) +50256*a(n-13) -37692*a(n-14) +22464*a(n-15) -89856*a(n-16) +67392*a(n-17) -15552*a(n-18) +62208*a(n-19) -46656*a(n-20)

EXAMPLE

Some solutions for n=2

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

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

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

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

CROSSREFS

Sequence in context: A251784 A234315 A251783 * A237953 A237236 A090006

Adjacent sequences:  A224642 A224643 A224644 * A224646 A224647 A224648

KEYWORD

nonn

AUTHOR

R. H. Hardin Apr 13 2013

STATUS

approved

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Last modified January 25 16:42 EST 2020. Contains 331245 sequences. (Running on oeis4.)