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 A099912 Number of closed walks on the Herschel graph. 1
 1, 4, 32, 328, 3560, 39064, 429512, 4724248, 51965960, 571624024, 6287861192, 69166466968, 760831124360, 8369142343384, 92060565728072, 1012666222910488, 11139328451818760, 122532612969613144, 1347858742664958152 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Counts closed walks of length 2n at any node of degree 4 on the Herschel graph. With interpolated zeros, counts closed walks of length n. The g.f. is then (1-9x^2+2x^4)/((1-2x^2)(1-11x^2))=(1-14x^2+53x^4-64x^6+12x^8)/((1-2x^2)^2(1-3x^2)(1-11x^2)). Binomial transform of A099913. LINKS Table of n, a(n) for n=0..18. Eric Weisstein's World of Mathematics, Herschel Graph FORMULA G.f. : (1-9x+2x^2)/((1-2x)(1-11x)); a(n)=0^n/11+811^(n-1)/3+2^(n+1)/3. CROSSREFS Sequence in context: A357404 A061631 A291342 * A362676 A272823 A002005 Adjacent sequences: A099909 A099910 A099911 * A099913 A099914 A099915 KEYWORD easy,nonn AUTHOR Paul Barry, Oct 30 2004 STATUS approved

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Last modified March 1 20:05 EST 2024. Contains 370443 sequences. (Running on oeis4.)