A019762 Decimal expansion of 2*e.

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

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• cons

Comments

Simple continued fraction is A081750. - Michael Somos, May 07 2012

Equals Sum_{n>=1} n^2/n!. - Arkadiusz Wesolowski, Mar 11 2013

Equals lim_{x->1} (x*e^x - e)/(x-1). Also 2*e = Sum_{n>=0} Sum_{k=0..n} 1/n!. - Richard R. Forberg, Dec 23 2014

Equals 1 + (2/1) + (3/2/1) + (4/3/2/1) + (5/4/3/2/1) + (6/5/4/3/2/1) + ... . - Davide Rotondo, Apr 07 2024

Examples

			2*e = 5.43656365691809047072057494270532499551449418739991914993...
		

Links

• Ivan Panchenko, Table of n, a(n) for n = 1..1000
• Index entries for transcendental numbers

Crossrefs

Cf. A001113, A081750 (continued fraction), A081749 (continued fraction of e/5 = 0.543...).

Programs

Mathematica

RealDigits[N[2*E, 105]][[1]] (* Arkadiusz Wesolowski, Mar 11 2013 *)

PARI

2*exp(1) \\ Charles R Greathouse IV, Oct 02 2022