Sylvester's sequence: Difference between revisions

=={{header|Ruby}}==

<lang ruby>def sylvester(n) = (1..n).reduce(2){|a| a*a - a + 1 }

(0..9).each {|n| puts "#{n}: #{sylvester n}" }

puts "

Sum of reciprocals of first 10 terms:

#{(0..9).sum{|n| 1.0r / sylvester(n)}.to_f }"

</lang>

{{out}}

<pre>0: 2

1: 3

2: 7

3: 43

4: 1807

5: 3263443

6: 10650056950807

7: 113423713055421844361000443

8: 12864938683278671740537145998360961546653259485195807

9: 165506647324519964198468195444439180017513152706377497841851388766535868639572406808911988131737645185443

Sum of reciprocals of first 10 terms:

1.0

</pre>