%I #18 Sep 08 2022 08:45:45
%S 4,6,13,27,50,84,131,193,272,370,489,631,798,992,1215,1469,1756,2078,
%T 2437,2835,3274,3756,4283,4857,5480,6154,6881,7663,8502,9400,10359,
%U 11381,12468,13622,14845,16139,17506,18948,20467,22065,23744,25506,27353,29287
%N a(n) = (2*n^3 + 9*n^2 + n + 24) / 6.
%C Arithmetic progression of third order; a(n+1)-a(n) = A008865(n+2);
%C a(n) = A101986(n) + 4.
%D R. Courant, Differential and Integral Calculus Vol. I (Blackie&Son, 1937), ch. I.4, Example 5, p.29.
%H Vincenzo Librandi, <a href="/A160805/b160805.txt">Table of n, a(n) for n = 0..1000</a>
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,-6,4,-1).
%F a(n) = (2*n^3 + 9*n^2 + n + 24) / 6.
%F From _Wesley Ivan Hurt_, Aug 29 2015: (Start)
%F G.f.: (4-10*x+13*x^2-5*x^3)/(x-1)^4.
%F a(n) = 4*a(n-1)-6*a(n-2)+4*a(n-3)-a(n-4), n>3. (End)
%p A160805:=n->(2*n^3+9*n^2+n+24)/6: seq(A160805(n), n=0..80); # _Wesley Ivan Hurt_, Aug 29 2015
%t Table[(2 n^3 + 9 n^2 + n + 24)/6, {n, 0, 60}]
%t CoefficientList[Series[(4 - 10*x + 13*x^2 - 5*x^3)/(x - 1)^4, {x, 0, 60}], x] (* _Wesley Ivan Hurt_, Aug 29 2015 *)
%o (Magma) [(2*n^3+9*n^2+n+24)/6: n in [0..50]]; // _Vincenzo Librandi_, Dec 27 2010
%o (PARI) first(m)=vector(m,i,i--;(2*i^3 + 9*i^2 + i + 24) / 6) \\ _Anders Hellström_, Aug 29 2015
%Y Cf. A008865, A101986.
%K nonn,easy
%O 0,1
%A _Reinhard Zumkeller_, May 26 2009