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A171970 Integer part of the height of an equilateral triangle with side length n. 5
0, 1, 2, 3, 4, 5, 6, 6, 7, 8, 9, 10, 11, 12, 12, 13, 14, 15, 16, 17, 18, 19, 19, 20, 21, 22, 23, 24, 25, 25, 26, 27, 28, 29, 30, 31, 32, 32, 33, 34, 35, 36, 37, 38, 38, 39, 40, 41, 42, 43, 44, 45, 45, 46, 47, 48, 49, 50, 51, 51, 52, 53, 54, 55, 56, 57, 58, 58, 59, 60, 61, 62, 63 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

a(n) = floor(A022838(n)/2);

a(n)*A004526(n) <= A171971(n);

a(n)*A005843(n) <= A171972(n).

LINKS

Table of n, a(n) for n=1..73.

Wikipedia, Equilateral triangle

Eric Weisstein's World of Mathematics, Equilateral Triangle

FORMULA

a(n) = floor(n*sqrt(3)/2).

PROG

(PARI) a(n)=sqrtint(3*n^2\4) \\ Charles R Greathouse IV, Jan 06 2013

CROSSREFS

Sequence in context: A145569 A213851 A172475 * A071377 A076946 A064524

Adjacent sequences:  A171967 A171968 A171969 * A171971 A171972 A171973

KEYWORD

nonn,easy

AUTHOR

Reinhard Zumkeller, Jan 20 2010

STATUS

approved

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Last modified May 21 07:04 EDT 2013. Contains 225477 sequences.