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A171974 Integer part of the height of a regular tetrahedron with edge length n. 5
0, 1, 2, 3, 4, 4, 5, 6, 7, 8, 8, 9, 10, 11, 12, 13, 13, 14, 15, 16, 17, 17, 18, 19, 20, 21, 22, 22, 23, 24, 25, 26, 26, 27, 28, 29, 30, 31, 31, 32, 33, 34, 35, 35, 36, 37, 38, 39, 40, 40, 41, 42, 43, 44, 44, 45, 46, 47, 48, 48, 49, 50, 51, 52, 53, 53, 54, 55, 56, 57, 57, 58, 59 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

-3 <= 4*A171975(n) - 3*a(n) < 3;

a(n)*A171975(n) <= A007590(n);

floor(a(n)*A171971(n)/3) <= A171973(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)/3).

PROG

(Haskell)

a171974 = floor . (/ 3) . (* sqrt 6) . fromInteger

-- Reinhard Zumkeller, Dec 15 2012

CROSSREFS

Cf. A171972, A022840.

Sequence in context: A120507 A303787 A090223 * A232748 A187737 A109401

Adjacent sequences:  A171971 A171972 A171973 * A171975 A171976 A171977

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Jan 20 2010

STATUS

approved

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Last modified February 20 21:05 EST 2019. Contains 320347 sequences. (Running on oeis4.)