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A033584
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a(n) = 11*n^2.
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10
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0, 11, 44, 99, 176, 275, 396, 539, 704, 891, 1100, 1331, 1584, 1859, 2156, 2475, 2816, 3179, 3564, 3971, 4400, 4851, 5324, 5819, 6336, 6875, 7436, 8019, 8624, 9251, 9900, 10571, 11264, 11979, 12716
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OFFSET
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0,2
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COMMENTS
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LINKS
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FORMULA
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Sum_{n>=1} 1/a(n) = Pi^2/66.
Sum_{n>=1} (-1)^(n+1)/a(n) = Pi^2/132.
Product_{n>=1} (1 + 1/a(n)) = sqrt(11)*sinh(Pi/sqrt(11))/Pi.
Product_{n>=1} (1 - 1/a(n)) = sqrt(11)*sin(Pi/sqrt(11))/Pi. (End)
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EXAMPLE
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a(1)=22*1+0-11=11; a(2)=22*2+11-11=44; a(3)=22*3+44-11=99 - Vincenzo Librandi, Aug 05 2010
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MATHEMATICA
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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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