document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=104415>Question 104415</A>: <I><SPAN STYLE=\"word-break: break-all;\"> how do you figure out the equation for rectangular numbers?\r<BR>\n" );
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document.write( "ex. the first term is 1, there are 2 dots, the second term is 2, there are 6 dots, the third term is 3, there are 12 dots. <BR>\n" );
document.write( "I see that the first difference is 2 more than the previous, and the second difference is 2, but how do i write this in an equation? Thank you. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #75950 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=75950\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> n(n+1) gives the sequence<BR>\n" );
document.write( "1*2=2<BR>\n" );
document.write( "2*3=6<BR>\n" );
document.write( "3*4=12<BR>\n" );
document.write( "4*5=20<BR>\n" );
document.write( "etc.<BR>\n" );
document.write( "=========<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
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