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 A304960 Number of business cards required to build an origami level n Mosely snowflake sponge. 1
 12, 168, 2784, 48912, 874416, 15709488, 282620784, 5086424112, 91551884016, 1647915162288, 29662379171184, 533922356331312, 9610600070213616, 172990789545095088, 3113834153217961584, 56049014464954558512, 1008882258904338303216, 18159880652953870707888 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 REFERENCES Thomas Hull, Project Origami: Activities for Exploring Mathematics, A K Peters/CRC Press, 2006. LINKS Franck Ramaharo, Level Two Mosely Snowflake Sponge Origami Resource Center, Business Card Origami Origami Resource Center, Mosely Snowflake Sponge Fractal (Level 3) The Institute For Figuring, The Mosely Snowflake Sponge at the USC Libraries The Institute For Figuring, USC Sponge Guide Wikipedia, Mosely snowflake Index entries for linear recurrences with constant coefficients, signature (23,-90) FORMULA a(n) = (108*18^n + 48*5^n)/13. a(n) = 18*a(n-1) - 48*5^(n - 1); a(n) = 23*a(n-1) - 90*a(n-2), with a(0) = 12 and a(1) = 168. G.f.: - 12*(9*x - 1)/((5*x - 1)*(18*x - 1)). E.g.f.: (108*exp(18*x) + 48*exp(5*x))/13. EXAMPLE a(1) = 168 because 108 business cards are needed for the squeleton and 60 more for the panels (see guide in links). MAPLE seq((108*18^n + 48*5^n)/13, n = 0 .. 50); MATHEMATICA LinearRecurrence[{23, -90}, {12, 168}, 50] PROG (Maxima) makelist((108*18^n + 48*5^n)/13, n, 0, 50); CROSSREFS Cf. A212596 (Origami Menger sponge). Sequence in context: A216702 A320761 A282045 * A113380 A071103 A012489 Adjacent sequences:  A304957 A304958 A304959 * A304961 A304962 A304963 KEYWORD nonn,easy AUTHOR Franck Maminirina Ramaharo, May 22 2018 STATUS approved

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Last modified August 10 07:37 EDT 2020. Contains 336368 sequences. (Running on oeis4.)