A084835 - OEIS

%I #9 Apr 12 2019 15:35:08

%S 0,0,0,0,0,1,2,5,10,18,30,49,75,112,163,231,322,441,595,792,1045,1361,

%T 1760,2255,2871,3626,4559,5691,7077,8750,10780,13216,16156,19662,

%U 23868,28866,34828,41882,50262,60138

%N a(n) = A000094(n+4) - A006918(n).

%C Also the number of integer partitions of n - 3 with Durfee square of length > 2, i.e., those with at least 3 parts > 2. The Heinz numbers of these partitions are given by A307515. - _Gus Wiseman_, Apr 12 2019

%p A084845 := proc(n)

%p     A000094(n+4)-A006918(n)

%p end proc:

%p seq(A084845(n),n=1..40) ; # _R. J. Mathar_, May 17 2016

%t durf[ptn_]:=Length[Select[Range[Length[ptn]],ptn[[#]]>=#&]];

%t Table[Length[Select[IntegerPartitions[n],durf[#]>2&]],{n,0,30}] (* _Gus Wiseman_, Apr 12 2019 *)

%Y Cf. A000094, A006918, A096771, A115720, A257990, A307515, A325164, A325192.

%K nonn

%O 1,7

%A _Jon Perry_, Jul 12 2003