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A171975 Integer part of the circumsphere radius of a regular tetrahedron with edge length n. 4
0, 1, 1, 2, 3, 3, 4, 4, 5, 6, 6, 7, 7, 8, 9, 9, 10, 11, 11, 12, 12, 13, 14, 14, 15, 15, 16, 17, 17, 18, 18, 19, 20, 20, 21, 22, 22, 23, 23, 24, 25, 25, 26, 26, 27, 28, 28, 29, 30, 30, 31, 31, 32, 33, 33, 34, 34, 35, 36, 36, 37, 37, 38, 39, 39, 40, 41, 41, 42, 42, 43, 44, 44, 45, 45 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

-3 <= 4*a(n) - 3*A171974(n) < 3;

a(n)*A171974(n) <= A007590(n).

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

Wikipedia, Tetrahedron

Eric Weisstein's World of Mathematics, Tetrahedron

FORMULA

a(n) = floor(n*sqrt(6)/4).

PROG

(Haskell)

a171975 = floor . (/ 4) . (* sqrt 6) . fromInteger

-- Reinhard Zumkeller, Dec 15 2012

CROSSREFS

Cf. A171973, A171972, A022840.

Sequence in context: A244229 A317596 A057355 * A160511 A079952 A055930

Adjacent sequences:  A171972 A171973 A171974 * A171976 A171977 A171978

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Jan 20 2010

STATUS

approved

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Last modified March 26 04:32 EDT 2019. Contains 321481 sequences. (Running on oeis4.)