A212040 - OEIS

A212040

Number of lower triangular n X n arrays colored with integers 0 upwards introduced in row major order, with no element equal to any element within a city block distance of two, and containing the value n(n+1)/2-3

0, 1, 5, 119, 1310, 7849, 32696, 107400, 298404, 731960, 1630174, 3361016, 6505445, 11945114, 20974435, 35441099, 57919461, 91921515, 142150499, 214802485, 317921624, 461815031

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OFFSET

1,3

COMMENTS

Column 2 of A212044

LINKS

Table of n, a(n) for n=1..22.

FORMULA

Empirical: a(n) = (1/128)*n^8 + (1/32)*n^7 - (77/192)*n^6 - (3/16)*n^5 + (977/128)*n^4 - (1885/96)*n^3 + (1129/96)*n^2 + (355/24)*n - 15 for n>1

EXAMPLE

Some solutions for n=4

..0........0........0........0........0........0........0........0