login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A071398 Rounded total surface area of a regular icosahedron with edge length n. 5
0, 9, 35, 78, 139, 217, 312, 424, 554, 701, 866, 1048, 1247, 1464, 1697, 1949, 2217, 2503, 2806, 3126, 3464, 3819, 4192, 4581, 4988, 5413, 5854, 6313, 6790, 7283, 7794, 8323, 8868, 9431, 10011, 10609, 11224, 11856, 12505, 13172, 13856, 14558, 15277 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

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

Eric Weisstein's World of Mathematics, Platonic Solid

FORMULA

a(n) = round(5 * n^2 * sqrt(3)).

EXAMPLE

a(4)=139 because round(5*4^2*sqrt(3)) = round(80*1.73205...) = round(138.56...) = 139.

MATHEMATICA

With[{c=5Sqrt[3]}, Round[c Range[0, 50]^2]] (* Harvey P. Dale, May 20 2011 *)

PROG

(PARI) for(n=0, 100, print1(round(5*n^2*sqrt(3)), ", "))

(MAGMA) [Round(5 * n^2 * Sqrt(3)): n in [0..50]]; // Vincenzo Librandi, May 21 2011

CROSSREFS

Cf. A070169 (tetrahedron), A033581 (cube), A071396 (octahedron), A071397 (dodecahedron), A071402 (volume of icosahedron).

Sequence in context: A033566 A226755 A022275 * A212099 A212100 A005898

Adjacent sequences:  A071395 A071396 A071397 * A071399 A071400 A071401

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 20 00:50 EDT 2018. Contains 316378 sequences. (Running on oeis4.)