document.write( "Question 1049661: Find the 25th term in the sequence 0, 3, 8, 15, 24, 35, ..........
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Algebra.Com's Answer #665261 by MathLover1(20850)\"\" \"About 
You can put this solution on YOUR website!
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\n" ); document.write( "\n" ); document.write( "Find the 25th term in the sequence \"0\", \"3\", \"8\", \"15\", \"24\",\"+35\", ..........\r
\n" ); document.write( "\n" ); document.write( "The sequence of differences is:\r
\n" ); document.write( "\n" ); document.write( "\"0\", .....\"3\",..... \"8\",..... \"15\",..... \"24\",.....\"+35\",
\n" ); document.write( ".....\"3\"......\"5\"........\"7\".......\"9\"...........\"11\"->first differences consecutive odd numbers
\n" ); document.write( ".........\"2\".......\"2\".......\"2\"...........\"2\"...->second differences same, so no need to go further\r
\n" ); document.write( "\n" ); document.write( "I happen to know that the sum of consecutive odd numbers is a square:\r
\n" ); document.write( "\n" ); document.write( " \"1+%2B+3+=+4\"
\n" ); document.write( " \"1+%2B+3+%2B+5+=+9\"
\n" ); document.write( " \"1+%2B+3+%2B+5+%2B+7+=+16\".....and so on. \r
\n" ); document.write( "\n" ); document.write( "The formula for this is\r
\n" ); document.write( "\n" ); document.write( " \"1+%2B+3+%2B+5\" + ... +\"+%282n-1%29+=+n%5E2\"\r
\n" ); document.write( "\n" ); document.write( "Your sequence is just my sum with \"1\" removed from the start! So the
\n" ); document.write( "formula is:\r
\n" ); document.write( "\n" ); document.write( " \"a%5Bn%5D+=+n%5E2+-+1\" (for all terms given)\r
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\n" ); document.write( "\n" ); document.write( "then the 25th term in the sequence is:\r
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\n" ); document.write( "\n" ); document.write( "\"a%5B25%5D+=+25%5E2+-+1\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B25%5D+=+625+-+1\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B25%5D+=+624\"\r
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\n" ); document.write( "\n" ); document.write( "here it is:
\n" ); document.write( "{0, 3, 8, 15, 24, 35, 48, 63, 80, 99, 120, 143, 168, 195, 224, 255, 288, 323, 360, 399, 440, 483, 528, 575, \"624\", 675, 728, 783, 840, 899, 960, 1023, 1088, 1155, 1224, 1295, 1368, 1443}....\r
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