

A179048


Decimal expansion of 25*sqrt(3)/4, the area of the equilateral triangle of side 5.


1



1, 0, 8, 2, 5, 3, 1, 7, 5, 4, 7, 3, 0, 5, 4, 8, 3, 0, 8, 4, 5, 4, 6, 5, 3, 9, 6, 3, 4, 4, 1, 1, 7, 0, 2, 2, 9, 3, 3, 9, 2, 5, 3, 2, 8, 3, 6, 3, 1, 4, 8, 7, 8, 9, 2, 5, 3, 4, 8, 7, 9, 3, 6, 2, 1, 5, 7, 4, 5, 8, 1, 3, 5, 5, 6, 8, 0, 0, 0, 0, 2, 3, 1, 7, 5, 7, 1, 6, 3, 6, 6, 7, 2, 3, 2, 8, 0, 3, 5, 9, 7, 9, 7, 2, 6
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OFFSET

2,3


REFERENCES

Mohammad K. Azarian, A Trigonometric Characterization of Equilateral Triangle, Problem 336, Mathematics and Computer Education, Vol. 31, No. 1, Winter 1997, p. 96. Solution published in Vol. 32, No. 1, Winter 1998, pp. 8485.
Mohammad K. Azarian, Equating Distances and Altitude in an Equilateral Triangle, Problem 316, Mathematics and Computer Education, Vol. 28, No. 3, Fall 1994, p. 337. Solution published in Vol. 29, No. 3, Fall 1995, pp. 324325.


LINKS

Table of n, a(n) for n=2..106.


FORMULA

Equals 25*A002194/4.


EXAMPLE

10.825317547305483084546539634411702293392532836314878925348793621574581355680..


MATHEMATICA

a=b=c=5; area=Sqrt[(a+bc)*(ab+c)*(a+b+c)*(a+b+c)]/4; RealDigits[N[area, 200]]
RealDigits[(25*Sqrt[3])/4, 10, 120][[1]] (* Harvey P. Dale, May 30 2018 *)


PROG

(PARI) 25*sqrt(3)/4 \\ Charles R Greathouse IV, Jun 30 2011


CROSSREFS

Cf. A002194, A010502, A120011, A179047.
Sequence in context: A284157 A201583 A243370 * A173158 A020787 A179954
Adjacent sequences: A179045 A179046 A179047 * A179049 A179050 A179051


KEYWORD

nonn,cons,easy


AUTHOR

Vladimir Joseph Stephan Orlovsky, Jun 26 2010


EXTENSIONS

Offset corrected, keyword:cons inserted  R. J. Mathar, Jun 28 2010


STATUS

approved



