Find the sum to n terms of 2+10+30+68+130.........?

Question

experimentx · Answer

hunt down the pattern.

experimentx · Answer

easy way ...plug the series in WA or OEIS ... but i suggest you look for difference or difference of difference.

anonymous · Answer

wat is WA and OEIS

experimentx · Answer

http://www.wolframalpha.com/ http://www.oeis.org/

anonymous · Answer

i want to do manually

anonymous · Answer

any other way

experimentx · Answer

yeah ... look for the difference of the terms, 
also difference of the difference
also try dividing by 2 , 3 ,4 , 5 ... 

the basic sequence are the arithmetic, geometric, oar arithmetic-geometric sequences  ...

anonymous · Answer

K th order Diffrence....is cumbersome.....

experimentx · Answer

find the first few ...

anonymous · Answer

3 rd order difference is Constant...

experimentx · Answer

write it down ... i haven't worked it out.

anonymous · Answer

hm...Is there any other way to tackle this

experimentx · Answer

at least i can't tell by looking ...

experimentx · Answer

if you say the third order difference is constant ... then it must be sequence of sums of Arithmetic sequence.

anonymous · Answer

third differences are 6

anonymous · Answer

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experimentx · Answer

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