A087197 Decimal expansion of 1/sqrt(Pi).

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

Offset: 0

Author

Sven Simon, Aug 24 2003

Keywords

• cons
• easy
• nonn

Comments

Radius of a circle with area 1.

Expectation of the maximum of a size 2 sample from a normal (0,1) distribution. - Jean-François Alcover, Jun 05 2014

Examples

			0.56418958354775628694...
		

References

• Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 5.16 Extreme value constants, p. 365.

Links

• G. C. Greubel, Table of n, a(n) for n = 0..5000
• Eric Weisstein's World of Mathematics, Inverse Erf
• Index entries for transcendental numbers

Crossrefs

Cf. A086201, A087198, A087199.

Programs

Mathematica

RealDigits[1/Sqrt[Pi], 10, 50][[1]] (* G. C. Greubel, Jan 09 2017 *)

PARI

Pi^-.5 \\ Charles R Greathouse IV, Nov 13 2015

Formula

Equals lim_{n -> infinity} Catalan(n)/(4^n*n^(-3/2)). - Jean-François Alcover, May 23 2013

Equals Sum_{k>=1} k/(2^k * Gamma(k+3/2)). - Amiram Eldar, May 27 2021