This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A250856 Number of (4+1) X (n+1) 0..3 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction. 1
 12311, 63631, 223933, 626416, 1499679, 3204951, 6279401, 11485528, 19866631, 32808359, 52106341, 80039896, 119451823, 173834271, 247420689, 345283856, 473439991, 638958943, 850080461, 1116336544, 1448679871, 1859618311 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = (76/9)*n^6 + (1595/12)*n^5 + (28765/36)*n^4 + (31373/12)*n^3 + (155683/36)*n^2 + (10223/3)*n + 1024. Conjectures from Colin Barker, Nov 21 2018: (Start) G.f.: x*(12311 - 22546*x + 37047*x^2 - 35749*x^3 + 21160*x^4 - 7167*x^5 + 1024*x^6) / (1 - x)^7. a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7) for n>7. (End) EXAMPLE Some solutions for n=2: ..0..0..0....3..3..1....3..1..0....2..2..2....3..3..3....3..2..1....3..3..3 ..3..3..3....1..1..1....0..0..0....1..1..1....0..0..0....0..0..0....2..3..3 ..1..1..1....2..2..2....0..0..0....1..1..1....0..0..0....2..2..2....1..2..2 ..3..3..3....0..1..1....0..0..0....0..3..3....0..0..0....0..0..0....0..1..1 ..0..0..0....1..2..3....1..2..2....0..3..3....2..2..2....0..0..0....0..1..1 CROSSREFS Row 4 of A250853. Sequence in context: A061745 A251776 A045084 * A242716 A077186 A077189 Adjacent sequences:  A250853 A250854 A250855 * A250857 A250858 A250859 KEYWORD nonn AUTHOR R. H. Hardin, Nov 28 2014 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 14 22:42 EST 2019. Contains 329987 sequences. (Running on oeis4.)