|
Search: id:A135918
|
|
|
| A135918 |
|
Genus of stage-n Menger sponge. |
|
+0
2
|
|
| 0, 5, 81, 1409, 26433, 514625, 10180161, 202704449, 4046898753, 80880453185, 1617148888641, 32339296372289, 646756476241473, 12934893915194945, 258695993426822721, 5173904789519844929, 103477975158264022593
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
REFERENCES
|
C. Mackeprang & K. Myers, Coloring Graphs on Sponges, Problem 11208, Amer. Math. Monthly 114 (November 2007), solutions p. 842.
|
|
FORMULA
|
(21*20^n + 38*8^n - 59)/133
|
|
EXAMPLE
|
a(0)=0 because a cube has genus 0. a(1)=5 because a cube with holes drilled through the faces meeting in the center has genus 5.
|
|
CROSSREFS
|
Cf. A135919.
Adjacent sequences: A135915 A135916 A135917 this_sequence A135919 A135920 A135921
Sequence in context: A144344 A062364 A110257 this_sequence A115032 A009733 A009756
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Marc LeBrun (mlb(AT)well.com), Dec 05 2007
|
|
|
Search completed in 0.002 seconds
|
