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A125200
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n*(4*n^2 + n -1)/2.
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2
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2, 17, 57, 134, 260, 447, 707, 1052, 1494, 2045, 2717, 3522, 4472, 5579, 6855, 8312, 9962, 11817, 13889, 16190, 18732, 21527, 24587, 27924, 31550, 35477, 39717, 44282, 49184, 54435, 60047, 66032, 72402, 79169, 86345, 93942, 101972, 110447, 119379
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| a(n) = Sum(4*n*k - n - k: 1<=k<=n), sums of rows of the triangle in A125199.
A003415(A003415(a(n))) = 2*A016969(n-1).
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FORMULA
| a(n)= 4*a(n-1) -6*a(n-2) +4*a(n-3) -a(n-4). G.f.: x*(2+9*x+x^2)/(x-1)^4. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Feb 12 2010]
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PROG
| (MAGMA)[n*(4*n^2 +n-1)div 2:n in [1..40]]; [From Vincenzo Librandi, Dec 27 2010]
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CROSSREFS
| Sequence in context: A192345 A125609 A100518 * A175450 A071402 A191295
Adjacent sequences: A125197 A125198 A125199 * A125201 A125202 A125203
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KEYWORD
| nonn
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AUTHOR
| Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Nov 24 2006
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EXTENSIONS
| Definition corrected by Vincenzo Librandi, Dec 27 2010
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