Subject: Re: Number series
Date: Wed, 9 Apr 1997 17:49:27 -0400
From: Alexander Bogomolny

The series consists of

one 1, two 2s, three 3s, ...

The sum of all numbers from 1 through n equals Sn = n(n+1)/2. You are looking for an n such that Sn < 1000000 but Sn+1 > 1000000. This number is 1413.

How do you get it? n*(n+1) < (n+1)2 < 2000000.

sqrt(2000000) is approximately 1414.2... So n+1=1414.

Regards

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