OFFSET
1,1
COMMENTS
Column 7 of A253424.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = a(n-1) +4*a(n-4) -4*a(n-5) -6*a(n-8) +6*a(n-9) +4*a(n-12) -4*a(n-13) -a(n-16) +a(n-17) for n>55.
Empirical for n mod 4 = 0: a(n) = (718127759360/3)*n^4 - (39490511684608/3)*n^3 + (14255146023889861/48)*n^2 - (38862279334406495/12)*n + 14257489007470705 for n>38.
Empirical for n mod 4 = 1: a(n) = (718127759360/3)*n^4 - 12729635040256*n^3 + (13453895148949957/48)*n^2 - (24046237081399511/8)*n + (209379461771811511/16) for n>38.
Empirical for n mod 4 = 2: a(n) = (718127759360/3)*n^4 - (41061416158208/3)*n^3 + (15381923770175941/48)*n^2 - (43432473054074767/12)*n + (65925438070533675/4) for n>38.
Empirical for n mod 4 = 3: a(n) = (718127759360/3)*n^4 - (36618000647168/3)*n^3 + (12344285144411077/48)*n^2 - (63323055557477789/24)*n + (175889901064136459/16) for n>38.
EXAMPLE
Some solutions for n=2
..0..3..2..3..2..3..4..4..3....0..3..2..3..2..2..3..4..3
..2..3..1..2..3..4..2..4..4....3..3..1..2..3..3..3..3..4
..2..1..3..3..2..3..4..4..3....2..1..3..2..2..3..3..4..4
..4..2..3..2..3..3..3..3..4....4..2..3..2..2..3..3..3..4
Knight distance matrix for n=2
..0..3..2..3..2..3..4..5..4
..3..4..1..2..3..4..3..4..5
..2..1..4..3..2..3..4..5..4
..5..2..3..2..3..4..3..4..5
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 31 2014
STATUS
approved