A225013
Number of 6Xn 0..1 arrays with rows unimodal and columns nondecreasing.
Original entry on oeis.org
7, 49, 252, 1036, 3612, 11088, 30738, 78354, 186142, 416394, 884236, 1794196, 3497248, 6577474, 11980667, 21201211, 36548573, 61520899, 101320712, 163556776, 259187048, 403770544, 619111172, 935394436, 1393938716, 2050706932
Offset: 1
Some solutions for n=3
..0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..1..0....1..1..0
..0..1..0....0..0..0....0..1..0....0..0..0....0..0..0....0..1..1....1..1..0
..0..1..0....1..0..0....0..1..1....0..1..0....1..0..0....0..1..1....1..1..0
..0..1..0....1..1..0....0..1..1....0..1..0....1..0..0....0..1..1....1..1..0
..1..1..0....1..1..0....1..1..1....0..1..0....1..0..0....0..1..1....1..1..1
..1..1..1....1..1..0....1..1..1....0..1..0....1..0..0....1..1..1....1..1..1
A225014
Number of 7Xn 0..1 arrays with rows unimodal and columns nondecreasing.
Original entry on oeis.org
8, 64, 372, 1716, 6672, 22716, 69498, 194634, 505912, 1233584, 2845492, 6251596, 13154948, 26635774, 52097267, 98759971, 181971248, 326703424, 572756312, 982365976, 1651162688, 2723729944, 4415408372, 7042481236, 11063492816
Offset: 1
Some solutions for n=3
..1..1..0....0..0..1....0..1..0....1..0..0....0..0..0....0..0..0....0..0..0
..1..1..0....0..0..1....1..1..0....1..0..0....0..1..0....0..0..0....0..1..0
..1..1..0....0..0..1....1..1..0....1..1..0....1..1..0....0..0..0....0..1..0
..1..1..0....0..0..1....1..1..0....1..1..0....1..1..0....0..0..1....1..1..0
..1..1..0....0..0..1....1..1..1....1..1..0....1..1..0....0..0..1....1..1..0
..1..1..0....0..1..1....1..1..1....1..1..1....1..1..1....0..1..1....1..1..0
..1..1..0....0..1..1....1..1..1....1..1..1....1..1..1....1..1..1....1..1..1
A228510
a(n) = (128*n^4/25+14528*n^3/225+20344*n^2/75+661816*n/1575+168)*(n+6)!/n!.
Original entry on oeis.org
120960, 4682880, 54268416, 364571136, 1758756096, 6759726336, 21978671616, 62815154688, 161990345088, 384087420288, 849090198528, 1768911326208, 3502103394816, 6633368787456, 12086145432576, 21278464551936, 36334471510656, 60366490588800
Offset: 0
For n=4 the solution is 1758756096.
- Index entries for linear recurrences with constant coefficients, signature (11,-55,165,-330,462,-462,330,-165,55,-11,1).
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m:=20; R:=PowerSeriesRing(Integers(), m); Coefficients(R!(1152*(105+2910*x+8168*x^2+4530*x^3+415*x^4)/(1-x)^11)); // Bruno Berselli, Oct 16 2013
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Table[(128 n^4/25 + 14528 n^3/225 + 20344 n^2/75 + 661816 n/1575 + 168) (n + 6)!/n!, {n, 0, 20}] (* Bruno Berselli, Oct 16 2013 *)
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