A019610 Decimal expansion of Pi*e/2.

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

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• cons

Examples

			4.26986711133678353273177543477328724751744426788255748...
		

References

• Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 2.15 Glaisher-Kinkelin constant, p. 136.

Links

• Ivan Panchenko, Table of n, a(n) for n = 1..1000
• Z. A. Melzak, Infinite products for πe and π/e, Amer. Math. Monthly 68 (1961) 39-41.

Crossrefs

Cf. A019609, A241420, A241421.

Programs

Magma

SetDefaultRealField(RealField(100)); R:= RealField(); Pi(R)*Exp(1)/2; // G. C. Greubel, Aug 24 2018

Maple

Digits:=100: evalf(Pi*exp(1)/2); # Wesley Ivan Hurt, Aug 09 2014

Mathematica

RealDigits[(Pi*E)/2,10,120][[1]] (* Harvey P. Dale, Apr 16 2014 *)

PARI

{ default(realprecision, 100); x=(1/2)*Pi*exp(1); for(n=1, 100, d=floor(x); x=(x-d)*10; print1(d, ", ")) } \\ Altug Alkan, Nov 13 2015

Formula

Melzak's formula: lim_{n->infinity} Product_{k=1..2n+1} (1+2/k)^(k*(-1)^(k+1)) = Pi*e/2. - Jean-François Alcover, Apr 25 2014