Sylvester's sequence: Difference between revisions

=={{header|Swift}}==

Using mkrd's BigNumber library.

<lang swift>import BigNumber

func sylvester(n: Int) -> BInt {

var a = BInt(2)

for _ in 0..<n {

a = a * a - a + 1

}

return a

}

var sum = BDouble(0)

for n in 0..<10 {

let syl = sylvester(n: n)

sum += BDouble(1) / BDouble(syl)

print(syl)

}

print("Sum of the reciprocals of first ten in sequence: \(sum)")</lang>

{{out}}

<pre>2

3

7

43

1807

3263443

10650056950807

113423713055421844361000443

12864938683278671740537145998360961546653259485195807

165506647324519964198468195444439180017513152706377497841851388766535868639572406808911988131737645185443

Sum of the reciprocals of first ten in sequence: 27392450308603031423410234291674686281194364367580914627947367941608692026226993634332118404582438634929548737283992369758487974306317730580753883429460344956410077034761330476016739454649828385541500213920805/27392450308603031423410234291674686281194364367580914627947367941608692026226993634332118404582438634929548737283992369758487974306317730580753883429460344956410077034761330476016739454649828385541500213920806</pre>