A252819 Number of nX7 nonnegative integer arrays with upper left 0 and every value within 2 of its city block distance from the upper left and every value increasing by 0 or 1 with every step right or down

22, 246, 2067, 13015, 65711, 279300, 1033761, 3414257, 10248688, 28359679, 73160199, 177550620, 408377425, 895696589, 1883020893, 3810974274, 7452779978, 14128342036, 26035049083, 46748705613, 81968236755, 140604294490

Offset

1,1

Comments

Column 7 of A252820

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 + (153973/907200)*n^7 + (4462807/7257600)*n^6 + (239717/145152)*n^5 + (50459/14400)*n^4 + (1240207/302400)*n^3 + (269664683/50450400)*n^2 + (308941/120120)*n + 4

Example

Some solutions for n=4
..0..1..1..2..3..4..5....0..1..2..3..4..5..5....0..1..2..3..3..4..4
..0..1..2..3..3..4..5....1..2..3..3..4..5..5....1..2..3..3..4..4..5
..1..2..3..3..4..5..6....2..3..3..4..5..6..6....1..2..3..4..5..5..6
..2..3..4..4..5..6..7....3..4..4..5..6..7..7....1..2..3..4..5..6..7

Crossrefs

Sequence in context: A249092 A125410 A200206 * A109251 A268791 A161521

Adjacent sequences: A252816 A252817 A252818 * A252820 A252821 A252822

Keyword

nonn

Author

R. H. Hardin, Dec 22 2014

Status

approved