A252825 Number of nX5 nonnegative integer arrays with upper left 0 and every value within 3 of its city block distance from the upper left and every value increasing by 0 or 1 with every step right or down.
15, 142, 1238, 9075, 54376, 271846, 1165921, 4396009, 14863460, 45791493, 130210765, 345350438, 861722537, 2037396931, 4591832266, 9915068062, 20600380173, 41336047432, 80360448168, 151781791285, 279198974102
Offset: 1
Keywords
Examples
Some solutions for n=4 ..0..1..1..2..3....0..1..1..2..2....0..1..2..3..3....0..1..2..2..2 ..1..2..2..3..3....0..1..1..2..3....1..2..3..3..3....1..1..2..2..3 ..2..2..3..3..3....1..1..1..2..3....1..2..3..4..4....1..2..3..3..4 ..3..3..3..4..4....1..2..2..3..4....1..2..3..4..4....2..3..4..4..5
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Formula
Empirical: a(n) = (29/130767436800)*n^15 + (29/1743565824)*n^14 + (761/1437004800)*n^13 + (4567/479001600)*n^12 + (156803/1437004800)*n^11 + (467/537600)*n^10 + (4895111/914457600)*n^9 + (8221817/304819200)*n^8 + (969313/9331200)*n^7 + (3241009/10886400)*n^6 + (129913907/179625600)*n^5 + (29795933/19958400)*n^4 + (1495061807/454053600)*n^3 + (185734933/50450400)*n^2 + (148987/27720)*n
Comments