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 A236755 Number of irregular spiral (expanded spiral) appearing with n center points. 1
 0, 2, 0, 16, 0, 720, 0, 35712, 0, 3628800, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS See A236535 for construction rule. Conjecture: (1) For even n; except n mod 4 = 0; all forms are expanded spirals and equal to n!. (2) For n mod 4 = 0, there are both non-expanded loops and expanded spirals. LINKS Kival Ngaokrajang, Illustration of irregular spirals, center points = 1..6 Kival Ngaokrajang, Small Basic program CROSSREFS Cf. A014105 (2 center points); A234902, A234903, A234904, A236535 (3 center points); A235088, A235089 (4 center points); A236326, A236327 (5 center  points). Sequence in context: A025600 A009006 A155585 * A057375 A009045 A060313 Adjacent sequences:  A236752 A236753 A236754 * A236756 A236757 A236758 KEYWORD nonn,more AUTHOR Kival Ngaokrajang, Jan 30 2014 STATUS approved

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Last modified January 18 13:42 EST 2019. Contains 319271 sequences. (Running on oeis4.)