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

5, 50, 353, 2201, 11932, 57146, 244818, 951917, 3403038, 11297855, 35123154, 102968348, 286360987, 759331583, 1928166887, 4706232142, 11076831313, 25210805133, 55622829033, 119222502647, 248739253915, 506020952898

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