> For the complete documentation index, see [llms.txt](https://trizen.gitbook.io/sidef-lang/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://trizen.gitbook.io/sidef-lang/programming_tasks/p/prime_reciprocal_sum.md).

# Prime reciprocal sum

```ruby
var A075442 = Enumerator({|callback|
    var sum = 0
    loop {
        var p = next_prime(ceil(1/(1-sum)))
        sum += 1/p
        callback(p)
    }
})

A075442.first(15).each_kv {|k,n|
    var s = Str(n)
    s = "#{s.first(20)}..#{s.last(20)} (#{s.len} digits)" if (s.len > 50)
    say "#{'%2d' % k+1}: #{s}"
}
```

#### Output:

```
 1: 2
 2: 3
 3: 7
 4: 43
 5: 1811
 6: 654149
 7: 27082315109
 8: 153694141992520880899
 9: 337110658273917297268061074384231117039
10: 84241975970641143191..13803869133407474043 (76 digits)
11: 20300753813848234767..91313959045797597991 (150 digits)
12: 20323705381471272842..21649394434192763213 (297 digits)
13: 12748246592672078196..20708715953110886963 (592 digits)
14: 46749025165138838243..65355869250350888941 (1180 digits)
15: 11390125639471674628..31060548964273180103 (2358 digits)
```


---

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