A128012 - OEIS

%I #11 Mar 11 2025 19:03:53

%S 3,3,6,9,12,15,21,24,30,36,42,48,57,63,72,81,90,99,111,120,132,144,

%T 156,168,183,195,210,225,240,255,273,288,306,324,342,360,381,399,420,

%U 441,462,483,507,528,552,576,600,624,651,675,702,729,756,783,813,840,870

%N a(n) = 3*A001399(n).

%C Total number of parts in all partitions of (n+3) into 3 parts. - _Alois P. Heinz_, Mar 11 2025

%H <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (1,1,0,-1,-1,1).

%F G.f.: -3/((x+1)*(x^2+x+1)*(x-1)^3). - _Alois P. Heinz_, Mar 11 2025

%Y Cf. A001399.

%K nonn,easy,less,changed

%O 0,1

%A _Thomas Wieder_, Feb 11 2007

%E More terms from _Robert G. Wilson v_, Feb 11 2007

%E Offset corrected by _Alois P. Heinz_, Sep 02 2020