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A177870 Decimal expansion of 3*Pi/4. 3
2, 3, 5, 6, 1, 9, 4, 4, 9, 0, 1, 9, 2, 3, 4, 4, 9, 2, 8, 8, 4, 6, 9, 8, 2, 5, 3, 7, 4, 5, 9, 6, 2, 7, 1, 6, 3, 1, 4, 7, 8, 7, 7, 0, 4, 9, 5, 3, 1, 3, 2, 9, 3, 6, 5, 7, 3, 1, 2, 0, 8, 4, 4, 4, 2, 3, 0, 8, 6, 2, 3, 0, 4, 7, 1, 4, 6, 5, 6, 7, 4, 8, 9, 7, 1, 0, 2, 6, 1, 1, 9, 0, 0, 6, 5, 8, 7, 8, 0, 0, 9, 8, 6, 6, 1, 1 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

As radians, this is equal to 135 degrees (on an analog clock, the span of 22 minutes and 30 seconds). - Alonso del Arte, Feb 03 2013

Ratio of the area of an arbelos to the area of its associated parbelos. - Jonathan Sondow, Nov 28 2013

REFERENCES

Jonathan Borwein & Peter Borwein, A Dictionary of Real Numbers. Pacific Grove, California: Wadsworth & Brooks/Cole Advanced Books & Software (1990) p. 168

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..10000

J. Sondow, The parbelos, a parabolic analog of the arbelos, arXiv 2012, Amer. Math. Monthly 120 (2013) 929-935.

E. Tsukerman, Solution of Sondow's problem: a synthetic proof of the tangency property of the parbelos, arXiv 2012.

FORMULA

Equals 0.75*A000796 = 3*A003881= 6*A019675 = A122952/4.

Equals 1 + (3/5) + (3*4)/(5*7) + (3*4*5)/(5*7*9) + ... = hypergeom([3,1],[5/2],1/2). - Peter Bala, Oct 30 2019

EXAMPLE

2.35619449019234492884698253745962716314787704953132936573120...

MAPLE

evalf(3*Pi/4) ;

MATHEMATICA

RealDigits[N[3(Pi/4), 110]][[1]]

CROSSREFS

Reciprocal of A232715.

Sequence in context: A226609 A157260 A291486 * A094872 A201744 A152206

Adjacent sequences:  A177867 A177868 A177869 * A177871 A177872 A177873

KEYWORD

nonn,cons,easy

AUTHOR

R. J. Mathar, Dec 13 2010

STATUS

approved

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Last modified November 22 02:58 EST 2019. Contains 329383 sequences. (Running on oeis4.)