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
Keywords
Examples
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
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
Comments