A236755 Number of irregular spiral (expanded spiral) appearing with n center points.

0, 2, 0, 16, 0, 720, 0, 35712, 0, 3628800, 0

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

Table of n, a(n) for n=1..11.

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: A009006 A155585 A350972 * A354416 A057375 A009045

Adjacent sequences: A236752 A236753 A236754 * A236756 A236757 A236758

Keyword

nonn,more

Author

Kival Ngaokrajang, Jan 30 2014

Status

approved