A252875 Number of nX7 nonnegative integer arrays with upper left 0 and lower right n+7-4 and value increasing by 0 or 1 with every step right or down

15, 211, 1948, 12686, 64920, 277585, 1030330, 3407823, 10237249, 28340232, 73128376, 177500233, 408299906, 895580310, 1882850350, 3810729118, 7452433875, 14127861337, 26034391284, 46747817584, 81967052716, 140602733711

Offset

1,1

Comments

Column 7 of A252876

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = (1/660441600)*n^14 + (1/9434880)*n^13 + (1/311850)*n^12 + (283/4989600)*n^11 + (23/34560)*n^10 + (5/896)*n^9 + (55843/1587600)*n^8 + (153793/907200)*n^7 + (4422487/7257600)*n^6 + (1152217/725760)*n^5 + (14953/4800)*n^4 + (834067/302400)*n^3 + (46071121/16816800)*n^2 - (359/17160)*n + 4

Example

Some solutions for n=3
..0..0..1..1..2..3..4....0..1..2..3..4..4..4....0..1..2..3..3..4..5
..1..1..2..2..3..4..5....1..2..3..4..4..5..5....1..2..2..3..4..5..6
..2..2..2..3..4..5..6....1..2..3..4..5..5..6....1..2..3..4..5..5..6

Crossrefs

Sequence in context: A001880 A240682 A113362 * A135519 A179091 A201340

Adjacent sequences: A252872 A252873 A252874 * A252876 A252877 A252878

Keyword

nonn

Author

R. H. Hardin, Dec 24 2014

Status

approved