document.write( "Question 352188: What would be an algebraic expression for the sequence 1,3,6, 10, 15, 21 and so on? \n" ); document.write( "

Algebra.Com's Answer #251668 by Fombitz(32388) $\"\"$ $\"About$

You can put this solution on YOUR website!
$\"a%5B1%5D=1\"$
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\n" ); document.write( " $\"a%5Bn%2B1%5D=a%5Bn%5D%2B%28n%2B1%29\"$
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\n" ); document.write( " $\"a%5B2%5D=a%5B1%5D%2B2=1%2B2=3\"$
\n" ); document.write( " $\"a%5B3%5D=a%5B2%5D%2B3=3%2B3=6\"$
\n" ); document.write( " $\"a%5B4%5D=a%5B3%5D%2B4=6%2B4=10\"$
\n" ); document.write( " $\"a%5B5%5D=a%5B4%5D%2B5=10%2B5=15\"$
\n" ); document.write( " $\"a%5B6%5D=a%5B5%5D%2B6=15%2B6=21\"$
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