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A119536
a(n) = 3*n^3 + 3*n.
0
0, 6, 30, 90, 204, 390, 666, 1050, 1560, 2214, 3030, 4026, 5220, 6630, 8274, 10170, 12336, 14790, 17550, 20634, 24060, 27846, 32010, 36570, 41544, 46950, 52806, 59130, 65940, 73254, 81090, 89466, 98400, 107910, 118014, 128730, 140076, 152070, 164730, 178074, 192120
OFFSET
0,2
FORMULA
a(n) = 3*A034262(n) = 6*A006003(n). - J. M. Bergot, Apr 16 2012
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4); a(0)=0, a(1)=6, a(2)=30, a(3)=90. - Harvey P. Dale, Mar 19 2013
From Elmo R. Oliveira, May 22 2026: (Start)
G.f.: 6*x*(1 + x + x^2)/(1 - x)^4.
E.g.f.: 3*x*(x + 1)*(x + 2)*exp(x).
a(n) = A008530(n)/2 for n > 0. (End)
MAPLE
[seq (3*n^3+3*n, n=0..60)];
MATHEMATICA
Table[3n^3+3n, {n, 0, 40}] (* Harvey P. Dale, Mar 19 2013 *)
(* Alternative: *)
LinearRecurrence[{4, -6, 4, -1}, {0, 6, 30, 90}, 40] (* Harvey P. Dale, Mar 19 2013 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Zerinvary Lajos, May 28 2006
EXTENSIONS
More terms from Elmo R. Oliveira, May 22 2026
STATUS
approved