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A227261 Number of nX4 0,1 arrays indicating 2X2 subblocks of some larger (n+1)X5 binary array having a sum of two or less, with rows and columns of the latter in lexicographically nondecreasing order 1
5, 50, 353, 2201, 11932, 57146, 244818, 951917, 3403038, 11297855, 35123154, 102968348, 286360987, 759331583, 1928166887, 4706232142, 11076831313, 25210805133, 55622829033, 119222502647, 248739253915, 506020952898 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 4 of A227263

LINKS

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

FORMULA

Empirical: a(n) = (1/1689515283456000)*n^19 + (43/1067062284288000)*n^18 + (1/1097800704000)*n^17 + (1/24908083200)*n^16 + (2161/2615348736000)*n^15 + (7723/10461394944000)*n^14 + (76931/201180672000)*n^13 + (38351/48283361280)*n^12 - (9767641/402361344000)*n^11 + (9434683/6967296000)*n^10 - (3668820107/402361344000)*n^9 - (5124736597/80472268800)*n^8 + (150774753091/72648576000)*n^7 - (42587741190289/3923023104000)*n^6 - (18276563116219/163459296000)*n^5 + (6577553955799/3113510400)*n^4 - (743180805841567/51459408000)*n^3 + (63341814516853/1286485200)*n^2 - (326223749821/4476780)*n + 17722 for n>9

EXAMPLE

Some solutions for n=4

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

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

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

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

CROSSREFS

Sequence in context: A301821 A301997 A227883 * A036291 A060347 A133646

Adjacent sequences:  A227258 A227259 A227260 * A227262 A227263 A227264

KEYWORD

nonn

AUTHOR

R. H. Hardin Jul 04 2013

STATUS

approved

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Last modified August 14 10:47 EDT 2020. Contains 336480 sequences. (Running on oeis4.)