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A045626 Bends in loxodromic sequence of spheres in which each 5 consecutive spheres are in mutual contact. 1
-1, 2, 3, 3, 5, 14, 23, 42, 81, 155, 287, 542, 1023, 1926, 3623, 6827, 12857, 24210, 45591, 85862, 161693, 304499, 573435, 1079898, 2033663, 3829802, 7212299, 13582227, 25578093, 48168758, 90711575, 170828354 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

H. S M Coxeter, 5 spheres in mutual contact, Abstracts AMS 18 (1997), p. 431, #924-05-202; also Math. Intell. 19(4) 1997 pp. 41-47.

LINKS

Table of n, a(n) for n=0..31.

FORMULA

G.f.: [ -2x^4-x^3+2x^2+3x-1]/[(1+x)(1-2x+x^2-2x^3+x^4)] (conjectured). - Ralf Stephan, May 06 2004

MAPLE

A045626 := proc(n) option remember; if n=0 then -1 elif n=1 then 2 elif n<=3 then 3 elif n=4 then 5 else A045626(n-1)+A045626(n-2)+A045626(n-3)+A045626(n-4)-A045626(n-5); fi; end;

CROSSREFS

Sequence in context: A064339 A174010 A053199 * A275914 A154923 A154693

Adjacent sequences:  A045623 A045624 A045625 * A045627 A045628 A045629

KEYWORD

sign

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified March 23 05:36 EDT 2019. Contains 321422 sequences. (Running on oeis4.)