A125961 Decimal expansion of e * sqrt(Pi) * erf(1).

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

Offset: 1

Author

Fredrik Johansson, Feb 06 2007

Keywords

• cons
• nonn

Examples

			c = 4.06015693855740995107817985133190089786512917863694504946039...
		

Links

• G. C. Greubel, Table of n, a(n) for n = 1..5000
• J.-P. Allouche and T. Baruchel, Variations on an error sum function for the convergents of some powers of e, arXiv preprint arXiv:1408.2206 [math.NT], 2014.

Programs

MATLAB

exp(1)*sqrt(pi)*erf(1) % Altug Alkan, Nov 11 2015

Mathematica

RealDigits[N[E Sqrt[Pi] Erf[1], 100]][[1]]

PARI

exp(1)*sqrt(Pi)*(1-erfc(1)) \\ Michel Marcus, Nov 11 2015

PARI

vector(100, n, if(n<1, 0, default(realprecision, n+2); floor((exp(1)*sqrt(Pi)*(1-erfc(1)))*10^(n-1))%10)) \\ Altug Alkan, Nov 11 2015

Formula

Equals Sum_{k >= 1} (2^k / (2k-1)!!).

Equals Integral_{x=0..1} e^x dx/sqrt(1-x). - Amiram Eldar, Jul 04 2020