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 A227556 Number of nX4 0,1 arrays indicating 2X2 subblocks of some larger (n+1)X5 binary array having nonzero determinant, with rows and columns of the latter in lexicographically nondecreasing order 1
 11, 81, 585, 3939, 23940, 130231, 635595, 2807533, 11342619, 42338997, 147335893, 481696118, 1489318226, 4378976416, 12302356074, 33158604442, 86042468013, 215601894342, 523073738362, 1231552044657, 2819779172382, 6289922485458 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Column 4 of A227558 LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = (1/39895087560007680000)*n^23 - (1/578189674782720000)*n^22 + (31/157688093122560000)*n^21 - (43/4505374089216000)*n^20 + (11/21332263680000)*n^19 - (10573/592812380160000)*n^18 + (2466337/4149686661120000)*n^17 - (360889/24409921536000)*n^16 + (14848109/44381675520000)*n^15 - (60304879/9963233280000)*n^14 + (74438290021/767168962560000)*n^13 - (3037062851/2360519884800)*n^12 + (1208999658479/81366405120000)*n^11 - (8787007618057/61024803840000)*n^10 + (276658611991/231154560000)*n^9 - (58139339838841/6974263296000)*n^8 + (3604676599939619/74101547520000)*n^7 - (17135686774664321/74101547520000)*n^6 + (16296634954448087/18665730720000)*n^5 - (2453303492285163517/985550582016000)*n^4 + (752720185790708953/150570227808000)*n^3 - (2634333865637083/430200650880)*n^2 + (1796305131851/594914320)*n + 933 for n>5 EXAMPLE Some solutions for n=4 ..0..0..0..0....0..0..0..1....0..0..1..0....0..0..0..1....0..0..1..1 ..0..0..0..1....0..0..1..0....0..1..0..1....0..0..1..0....0..1..1..1 ..0..0..1..0....1..1..0..0....0..1..0..1....0..1..1..1....0..1..1..0 ..1..0..0..0....1..1..1..0....1..1..0..1....1..1..1..0....1..0..0..0 CROSSREFS Sequence in context: A211557 A333061 A055429 * A181989 A199557 A003730 Adjacent sequences: A227553 A227554 A227555 * A227557 A227558 A227559 KEYWORD nonn AUTHOR R. H. Hardin Jul 16 2013 STATUS approved

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Last modified June 18 16:37 EDT 2024. Contains 373482 sequences. (Running on oeis4.)