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A082450
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a(n) = 5*(n^2-n+2)/2.
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1
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5, 5, 10, 20, 35, 55, 80, 110, 145, 185, 230, 280, 335, 395, 460, 530, 605, 685, 770, 860, 955, 1055, 1160, 1270, 1385, 1505, 1630, 1760, 1895, 2035, 2180, 2330, 2485, 2645, 2810, 2980, 3155, 3335, 3520, 3710, 3905, 4105, 4310, 4520, 4735, 4955, 5180, 5410, 5645
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OFFSET
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0,1
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COMMENTS
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Also the sum of five consecutive triangular numbers starting with A000217(-3). - Bruno Berselli, Jun 18 2015
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REFERENCES
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Found on a quiz.
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LINKS
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FORMULA
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a(0)=5, a(1)=5, a(2)=10; for n>2, a(n) = 3*a(n-1)-3*a(n-2)+a(n-3). - Harvey P. Dale, Mar 23 2013
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MATHEMATICA
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Table[(5(n^2-n+2))/2, {n, 0, 50}] (* or *) LinearRecurrence[{3, -3, 1}, {5, 5, 10}, 50] (* Harvey P. Dale, Mar 23 2013 *)
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PROG
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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