|
|
A189444
|
|
Number of n X 4 array permutations with each element moving zero or one space horizontally or diagonally.
|
|
1
|
|
|
5, 61, 666, 7300, 80282, 883049, 9712873, 106834338, 1175098084, 12925203122, 142167601085, 1563737653381, 17199948722346, 189186616701220, 2080911781577162, 22888478678939969, 251756206521753553
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
|
|
LINKS
|
|
|
FORMULA
|
Empirical: a(n) = 12*a(n-1) -12*a(n-2) +12*a(n-3) -12*a(n-4) +a(n-5).
Empirical g.f.: x*(5 + x - 6*x^2 - 20*x^3 + 2*x^4) / ((1 - x)*(1 - 11*x + x^2 - 11*x^3 + x^4)). - Colin Barker, May 02 2018
|
|
EXAMPLE
|
Some solutions for 3 X 4:
..0..1..3..2....1..0..2..3....5..1..2..3....5..1..3..2....0..6..2..3
..4..5..7..6....9.10.11..7....9..0..7..6....4..0..7..6....9..4..1..7
..9..8.11.10....8..4..5..6....8..4.11.10....8..9.11.10....8.10..5.11
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|