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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 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 June 13 00:57 EDT 2021. Contains 344980 sequences. (Running on oeis4.)