A139581 a(n) = n*(2*n + 19).
0, 21, 46, 75, 108, 145, 186, 231, 280, 333, 390, 451, 516, 585, 658, 735, 816, 901, 990, 1083, 1180, 1281, 1386, 1495, 1608, 1725, 1846, 1971, 2100, 2233, 2370, 2511, 2656, 2805, 2958, 3115, 3276, 3441, 3610, 3783, 3960, 4141
Offset: 0
Links
- Index entries for linear recurrences with constant coefficients, signature (3,-3,1).
Programs
-
Mathematica
Table[n(2n+19),{n,0,50}] (* Harvey P. Dale, Jan 26 2011 *) -
PARI
a(n)=n*(2*n+19) \\ Charles R Greathouse IV, Jun 17 2017
Formula
a(n) = 2*n^2 + 19*n.
a(n) = a(n-1) + 4*n + 17 (with a(0)=0). - Vincenzo Librandi, Nov 24 2010
From Elmo R. Oliveira, Nov 29 2024: (Start)
G.f.: x*(21 - 17*x)/(1-x)^3.
E.g.f.: exp(x)*x*(21 + 2*x).
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n > 2. (End)