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The sequence of numbers a1, a2, a3, . . . , an, [#permalink]
16 Aug 2018, 13:43
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The sequence of numbers a1, a2, a3, . . . , an, . . . is defined by an=an1 + n for each integer n ≥ 2 and a1=1. What is the value of a49?




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Re: The sequence of numbers a1, a2, a3, . . . , an, [#permalink]
16 Aug 2018, 22:17
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a2=a1+2 a3=a2+3   an=an1+n
sum them up => an=a1+2+3+...+n Since a1=1 => an=n(1+n)/2 => a49=1225



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Re: The sequence of numbers a1, a2, a3, . . . , an, [#permalink]
17 Aug 2018, 04:09
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natamiracle wrote: The sequence of numbers a1, a2, a3, . . . , an, . . . is defined by an=an1 + n for each integer n ≥ 2 and a1=1. What is the value of a49? Please read before posting: https://greprepclub.com/forum/rulesfor ... 1083.htmlPlease insert the official answer and under right tag in a separate POST. Due to not enough information this question is locked
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Re: The sequence of numbers a1, a2, a3, . . . , an,
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17 Aug 2018, 04:09





