A227383 Number of nX4 0,1 arrays indicating 2X2 subblocks of some larger (n+1)X5 binary array having a sum of one, with rows and columns of the latter in lexicographically nondecreasing order.
5, 30, 185, 1104, 6160, 31073, 141192, 581706, 2192737, 7631150, 24723499, 75114814, 215382006, 586096131, 1520882101, 3779307010, 9026380556, 20787492011, 46293089506, 99943655427, 209652253128, 428180495383
Offset: 1
Keywords
Examples
Some solutions for n=4 ..0..1..0..0....1..0..0..0....0..1..0..0....0..0..1..0....0..1..0..0 ..1..0..1..1....0..1..0..0....0..0..1..1....1..0..0..0....1..0..0..0 ..0..0..1..1....0..0..1..0....0..0..0..1....0..0..0..0....0..1..0..1 ..0..0..1..0....0..0..0..1....0..0..1..1....0..1..1..1....0..1..1..1
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Formula
Empirical: a(n) = (1/2534272925184000)*n^19 + (23/800296713216000)*n^18 + (31/29640619008000)*n^17 + (1061/31384184832000)*n^16 + (1/1793792000)*n^15 + (901/89159616000)*n^14 + (573137/7846046208000)*n^13 + (19320181/3621252096000)*n^12 - (25008281/201180672000)*n^11 + (332913253/109734912000)*n^10 - (5757514877/134120448000)*n^9 + (1008987604001/2414168064000)*n^8 - (7198243864451/3923023104000)*n^7 - (144244343741471/11769069312000)*n^6 + (12251347161947/40864824000)*n^5 - (164980284780767/59439744000)*n^4 + (28073158072/1786785)*n^3 - (35127268025713/617512896)*n^2 + (14284038375031/116396280)*n - 121172 for n>7
Comments