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%I #16 Mar 28 2015 16:40:02
%S 0,2,8,20,28,50,82,126,184,258,350,462,596,754,938,1150,1392,1666,
%T 1974,2318,2700,3122,3586,4094,4648,5250,5902,6606,7364,8178,9050,
%U 9982,10976,12034,13158,14350,15612,16946,18354,19838,21400,23042,24766,26574
%N If 0 <= n <= 3 then a(n) = n(n+1)(n+2)/3, if n >= 4 then a(n) = n(n^2+5)/3.
%C One way to generalize the magic number sequence in A018226.
%C See also A130598 and A162630.
%F From _Daniel Forgues_, May 03 2011: (Start)
%F If 0 <= n <= 3 then a(n) = 2 T_n, otherwise a(n) = 2 (T_n - t_{n-1}), where T_n is the n-th tetrahedral number, t_n the n-th triangular number.
%F G.f.: (2*x*(1 - 6*x^3 + 14*x^4 - 11*x^5 + 3*x^6))/(1 - x)^4, n >= 0.
%F (End)
%F a(n) = n*(n^2+5)/3 + (4*n-6)*A171386(n). - _Omar E. Pol_, Aug 14 2013
%Y Cf. A007290, A018226, A033547, A130598, A162518, A162519, A162521, A162522, A162523, A162524, A162525, A162630.
%K easy,nonn
%O 0,2
%A _Omar E. Pol_, Jul 07 2009, Jul 13 2009
%E Edited by _N. J. A. Sloane_, Jul 18 2009
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