Approximation of e

Jelly, 5 bytes


Try it online!

How it works

R’!İS  Main link. Argument: n

R      Yield the range [1, ..., n].
 ’     Map decrement over the list.
  !    Map factorial over the list.
   İ   Map inverse over the list.
    S  Compute the sum.

Wistful-C - 336 bytes

My first real wistful- program! There is actually a little golfing I did, with using someday instead of wait for because the first had a shorter length.

if only <stdio.h> were included...
if only int f were 1...
if only int N were 0...
wish for "%d",&N upon a star
if only int i were 0...
if only double e were 0...
someday i will be N...
        if only e were e+1./f...
        if only i were i+1...
        if only f were f*i...
wish "%f\n",e upon a star
if wishes were horses...

Pyth, 7 6 bytes


Try it here.

 m      map over range 0..input:
    .!  factorial
  c1    1 / ^
s       sum

Thanks to FryAmTheEggman for a byte!