|
| |
|
|
A103334
|
|
Number of closed walks of length 2n at any of the nodes of degree 1 on the graph of the (7,4) Hamming code.
|
|
1
| |
|
|
1, 1, 4, 24, 176, 1376, 10944, 87424, 699136, 5592576, 44739584, 357914624, 2863312896, 22906494976, 183251943424, 1466015514624, 11728124051456, 93824992280576, 750599937982464, 6004799503335424, 48038396025634816
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,3
|
|
|
COMMENTS
| a(n+1)=8^n/3+2^(n+1)/3 with g.f. (1-6x)/(1-10x+16x^2) counts walks of length 2n+1 between adjacent nodes of degrees 1 and 4 on the graph of the (7,4) Hamming code.
|
|
|
REFERENCES
| David J.C. Mackay, Information Theory, Inference and Learning Algorithms, CUP, 2003, p. 19.
|
|
|
FORMULA
| G.f.: (1-9x+10x^2)/(1-10x+16x^2); a(n)=8^(n-1)/3+2^(n)/3+5*0^n/8.
|
|
|
CROSSREFS
| Cf. A082412, A103333.
Sequence in context: A188913 A052685 A032349 * A156017 A000309 A112914
Adjacent sequences: A103331 A103332 A103333 * A103335 A103336 A103337
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| Paul Barry (pbarry(AT)wit.ie), Jan 31 2005
|
| |
|
|
