document.write( "Question 1184226: What is the formula to sum the \"n.n!\" where ! means factorial and n is finite positive integer? \n" ); document.write( "

Algebra.Com's Answer #814749 by ikleyn(52864) $\"\"$ $\"About$

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document.write( "The formula is\r\n" );
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document.write( "    1*1! + 2*2! + 3*3! + . . . + n*n! = (n+1)! - 1.\r\n" );
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document.write( "For the proof (quite easy) see this link\r\n" );
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document.write( "https://www.quora.com/What-is-the-sum-of-1-1-2-2-3-3-n-n\r\n" );
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