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 A331906 The number of regions inside a pentagram formed by the straight line segments mutually connecting all vertices and all points that divide the sides into n equal parts. 10
 40, 1100, 7330, 25540, 65930, 136200 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The terms are from numeric computation - no formula for a(n) is currently known. LINKS Scott R. Shannon, Pentagram regions for n = 1. Scott R. Shannon, Pentagram regions for n = 2. Scott R. Shannon, Pentagram regions for n = 3. Scott R. Shannon, Pentagram regions for n = 4. Scott R. Shannon, Pentagram regions for n = 5. Scott R. Shannon, Pentagram regions for n = 6. Scott R. Shannon, Pentagram regions with random distance-based coloring for n = 1. Scott R. Shannon, Pentagram regions with random distance-based coloring for n = 2. Scott R. Shannon, Pentagram regions with random distance-based coloring for n = 3. Scott R. Shannon, Pentagram regions with random distance-based coloring for n = 4. Scott R. Shannon, Pentagram regions with random distance-based coloring for n = 5. Eric Weisstein's World of Mathematics, Pentagram. CROSSREFS Cf. A331907 (n-gons), A333117 (vertices), A333118 (edges), A007678, A092867, A331452. Sequence in context: A284838 A124100 A071952 * A144914 A004385 A152257 Adjacent sequences:  A331903 A331904 A331905 * A331907 A331908 A331909 KEYWORD nonn,more AUTHOR Scott R. Shannon and N. J. A. Sloane, Jan 31 2020 STATUS approved

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Last modified April 8 21:44 EDT 2020. Contains 333329 sequences. (Running on oeis4.)