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A167614
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(n^2 + 3*n + 8)/2.
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3
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6, 9, 13, 18, 24, 31, 39, 48, 58, 69, 81, 94, 108, 123, 139, 156, 174, 193, 213, 234, 256, 279, 303, 328, 354, 381, 409, 438, 468, 499, 531, 564, 598, 633, 669, 706, 744, 783, 823, 864, 906, 949, 993, 1038, 1084, 1131, 1179, 1228, 1278, 1329, 1381, 1434, 1488
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OFFSET
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1,1
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COMMENTS
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A228446(a(n)) = 7. - Reinhard Zumkeller, Mar 12 2014
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LINKS
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Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (3,-3,1).
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FORMULA
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a(n) = n + a(n-1) + 1, with n>1, a(1)=6.
G.f:: x*(6-9*x+4*x^2)/(1-x)^3. - Vincenzo Librandi, Sep 16 2013
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MATHEMATICA
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Table[(n(n+3))/2+4, {n, 80}] (* Harvey P. Dale, Mar 24 2011 *)
CoefficientList[Series[(6 - 9 x + 4 x^2)/(1 - x)^3, {x, 0, 60}], x] (* Vincenzo Librandi, Sep 16 2013 *)
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PROG
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(PARI) a(n)=n*(n+3)/2+4 \\ Charles R Greathouse IV, Jan 11 2012
(MAGMA) [(n^2+3*n+8)/2: n in [1..60]]; // Vincenzo Librandi, Sep 16 2013
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CROSSREFS
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Sequence in context: A315963 A315964 A315965 * A020751 A315966 A315967
Adjacent sequences: A167611 A167612 A167613 * A167615 A167616 A167617
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KEYWORD
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nonn,easy
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AUTHOR
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Vincenzo Librandi, Nov 07 2009
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EXTENSIONS
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Corrected (changed one term from 1036 to 1038) by Harvey P. Dale, Mar 24 2011.
New name from Charles R Greathouse IV, Jan 11 2012
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STATUS
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approved
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