|
|
A153340
|
|
Number of zig-zag paths from top to bottom of a rectangle of width 8 with n rows.
|
|
1
|
|
|
8, 14, 26, 48, 90, 168, 316, 592, 1114, 2090, 3932, 7382, 13884, 26076, 49032, 92110, 173170, 325360, 611618, 1149248, 2160212, 4059360, 7629882, 14338290, 26949004, 50644750, 95185300, 178883252, 336200648, 631835054, 1187485194, 2231705808
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
Number of words of length n using an 8-symbol alphabet where neighboring letters are neighbors in the alphabet. - Andrew Howroyd, Apr 17 2017
|
|
LINKS
|
|
|
FORMULA
|
G.f.: 2*x*(4+3*x-6*x^2-2*x^3)/((1-x)*(1-3*x^2-x^3)). - Colin Barker, May 10 2012
|
|
MATHEMATICA
|
|
|
CROSSREFS
|
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|