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A125200 a(n) = n*(4*n^2 + n - 1)/2. 3
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; text; internal format)
OFFSET
1,1
COMMENTS
a(n) = Sum_{k=1..n} (4*n*k - n - k), sums of rows of the triangle in A125199.
A003415(A003415(a(n))) = 2*A016969(n-1).
LINKS
FORMULA
a(n) = 4*a(n-1) -6*a(n-2) +4*a(n-3) -a(n-4). - R. J. Mathar, Feb 12 2010
G.f.: x*(2+9*x+x^2)/(x-1)^4. - R. J. Mathar, Feb 12 2010
a(n) = Sum_{i=1..n} A033568(i). - Bruno Berselli, Jul 22 2013
MATHEMATICA
LinearRecurrence[{4, -6, 4, -1}, {2, 17, 57, 134}, 40] (* Harvey P. Dale, Feb 05 2013 *)
PROG
(Magma) [n*(4*n^2 +n-1)div 2:n in [1..40]]; // Vincenzo Librandi, Dec 27 2010
CROSSREFS
Sequence in context: A125609 A100518 A367032 * A368390 A175450 A071402
KEYWORD
nonn,easy
AUTHOR
Reinhard Zumkeller, Nov 24 2006
EXTENSIONS
Definition corrected by Vincenzo Librandi, Dec 27 2010
STATUS
approved

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Last modified March 29 01:36 EDT 2024. Contains 371264 sequences. (Running on oeis4.)