This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A071402 Rounded volume of a regular icosahedron with edge length n. 6
 0, 2, 17, 59, 140, 273, 471, 748, 1117, 1590, 2182, 2904, 3770, 4793, 5987, 7363, 8936, 10719, 12724, 14964, 17454, 20205, 23231, 26545, 30160, 34089, 38345, 42942, 47893, 53209, 58906, 64995, 71490, 78404, 85749, 93540, 101789, 110509 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS The printed reference given shows in a table on p. 10 that Volume is "2.18170a^3" (a is edge). Both PARI (see Example here) and a handheld calculator show that 2.18169 is correct for a 5-decimal-place approximation. REFERENCES S. Selby, editor, CRC Basic Mathematical Tables, CRC Press, 1970, pp. 10-11. LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..10000 Eric Weisstein's World of Mathematics, Icosahedron FORMULA a(n) = round(n^3 * (3+sqrt(5)) * 5/12). EXAMPLE a(6)=471 because round(6^3*(3 + sqrt(5))*5/12) = round(216*2.181694990...) = round(471.24...) = 471. PROG (PARI) for(n=0, 100, print1(round(n^3*(3+sqrt(5))*5/12), ", ")) (MAGMA) [Round(n^3 * (3+Sqrt(5)) * 5/12): n in [0..50]]; // Vincenzo Librandi, May 21 2011 CROSSREFS Cf. A000578 (cube), A071399 (tetrahedron), A071400 (octahedron), A071401 (dodecahedron), A071398 (total surface area of icosahedron). Cf. A102208 ((3+Sqrt(5)) * 5/12). Sequence in context: A100518 A125200 A175450 * A228641 A226417 A191295 Adjacent sequences:  A071399 A071400 A071401 * A071403 A071404 A071405 KEYWORD easy,nonn AUTHOR Rick L. Shepherd, May 29 2002 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified October 14 14:20 EDT 2019. Contains 328017 sequences. (Running on oeis4.)