login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A071401
Rounded volume of a regular dodecahedron with edge length n.
5
0, 8, 61, 207, 490, 958, 1655, 2628, 3924, 5586, 7663, 10200, 13242, 16836, 21028, 25863, 31388, 37649, 44691, 52561, 61305, 70968, 81597, 93237, 105935, 119736, 134687, 150833, 168221, 186896, 206904, 228292, 251105, 275390, 301191, 328556
OFFSET
0,2
REFERENCES
S. Selby, editor, CRC Basic Mathematical Tables, CRC Press, 1970, pp. 10-11.
LINKS
Eric Weisstein's World of Mathematics, Dodecahedron
FORMULA
a(n) = round(n^3 * (15+7*sqrt(5))/4)
EXAMPLE
a(6)=1665 because round(6^3*(15+7*sqrt(5))/4)=round(216*7.6631...)=round(1655.23...)=1665.
MATHEMATICA
Table[Floor[n^3 (15+7Sqrt[5])/4+1/2], {n, 0, 50}] (* Harvey P. Dale, Apr 25 2011 *)
PROG
(PARI) for(n=0, 100, print1(round(n^3*(15+7*sqrt(5))/4), ", "))
CROSSREFS
Cf. A000578 (cube), A071399 (tetrahedron), A071400 (octahedron), A071402 (icosahedron), A071397 (total surface area of dodecahedron).
Sequence in context: A034664 A242084 A007399 * A247535 A283852 A283410
KEYWORD
easy,nonn
AUTHOR
Rick L. Shepherd, May 29 2002
STATUS
approved