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 A160248 Table read by antidiagonals of "less regular" truncated tetrahedron numbers built of face-centered-cubic sphere packing. 0
 1, 6, 4, 19, 16, 10, 44, 40, 31, 20, 85, 80, 68, 52, 35, 146, 140, 125, 104, 80, 56, 231, 224, 206, 180, 149, 116, 84, 344, 336, 315, 284, 246, 204, 161, 120, 489, 480, 456, 420, 375, 324, 270, 216, 165 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS These also contain 3 existing sequences: 1: Regular octahedra (A005900) on the x-axis, which represents the increasing edge at truncation. 2: Regular tetrahedra (essentially A000292) on the y-axis, which represents the increasing remaining original edge. 3: Regular truncated tetrahedra (A005906) on the diagonal, which represents values where the newly formed edge and the remaining portion of the original tetrahedron edge are of equal length. REFERENCES Main Title: Polyhedra primer / Peter Pearce and Susan Pearce. Published/Created: New York : Van Nostrand Reinhold, c1978. Description: viii, 134 p. : ill. ; 24 cm. ISBN: 0442264968 Main Title: The book of numbers / John H. Conway, Richard K. Guy. Published/Created: New York, NY : Copernicus c1996. Description: ix, 310 p. : ill. (some col.) ; 24 cm. ISBN: 038797993X LINKS FORMULA v=(y^3+4*x^3+6*y^2*x+12*y*x^2-3*y^2-12*x^2-12*y*x+2*y+8*x)/6 PROG (Excel) Paste the following formula into cell C3, and fill down and right to desired table size. All volumes 10, 000 and under are covered by column AA and row 41. =((ROW()-2)^3+4*(COLUMN()-2)^3+6*(ROW()-2)^2*(COLUMN()-2)+12*(ROW()-2)*(COLUMN()-2)^2-3*(ROW()-2)^2-12*(COLUMN()-2)^2-12*(ROW()-2)*(COLUMN()-2)+2*(ROW()-2)+8*(COLUMN()-2))/6 CROSSREFS Sequence in context: A171089 A180495 A213761 * A317858 A212891 A107983 Adjacent sequences:  A160245 A160246 A160247 * A160249 A160250 A160251 KEYWORD easy,nonn,tabl AUTHOR Chris G. Spies-Rusk (chaosorder4(AT)gmail.com), May 05 2009, May 11 2009 EXTENSIONS Improvement of the definition's precision by Chris G. Spies-Rusk (chaosorder4(AT)gmail.com), May 19 2009 STATUS approved

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Last modified June 5 03:12 EDT 2020. Contains 334828 sequences. (Running on oeis4.)