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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. 2
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; text; 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.

LINKS

Table of n, a(n) for n=0..20.

Index entries for linear recurrences with constant coefficients, signature (10,-16).

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: A221088 A032349 A215709 * A156017 A000309 A112914

Adjacent sequences:  A103331 A103332 A103333 * A103335 A103336 A103337

KEYWORD

easy,nonn

AUTHOR

Paul Barry, Jan 31 2005

STATUS

approved

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Last modified January 27 12:01 EST 2020. Contains 331295 sequences. (Running on oeis4.)