OFFSET
1,3
COMMENTS
From J. Volkmar Schmidt, Oct 24 2023 (Start)
Proof of a(n) follows proof scheme from David A. Corneth for A186864.
Distribution matrix of surrounding rectangles for 8-step walks is:
[0 0 0 0 0 0 0 2]
[0 0 0 416 3264 4224 2304 508]
[0 0 2384 26004 38120 26164 10080 1764]
[0 416 26004 67424 53320 26480 8460 1328]
[0 3264 38120 53320 32032 13428 3816 560]
[0 4224 26164 26480 13428 4952 1260 172]
[0 2304 10080 8460 3816 1260 288 36]
[2 508 1764 1328 560 172 36 4]
(End)
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (3, -3, 1).
FORMULA
Empirical: a(n) = 550504*n^2 - 3839372*n + 6382124 for n > 6.
EXAMPLE
Some solutions for 4 X 4:
0 7 6 0 2 1 0 8 0 0 1 0 0 0 6 8 3 4 5 0
8 0 5 1 4 3 7 0 0 0 3 2 0 0 7 5 2 0 6 0
0 4 3 2 0 5 6 0 0 7 5 4 2 1 4 0 1 0 7 8
0 0 0 0 0 0 0 0 0 8 6 0 0 3 0 0 0 0 0 0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 27 2011
EXTENSIONS
a(12)-a(26) from J. Volkmar Schmidt, Aug 27 2023
STATUS
approved