This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A284640 #10 Apr 04 2025 22:28:45
%S A284640 1,1,4,4,7,13,17,23,34,49,62,87,112,149,199,249,318,408,512,635,820,
%T A284640 991,1238,1515,1864,2248,2770,3326,4030,4818,5808,6882,8290,9756,
%U A284640 11639,13719,16236,18999,22468,26144,30724,35761,41754,48357,56380,65018,75438
%N A284640 Number of positive subset sums of strict integer partitions of n.
%C A284640 For a strict integer partition p summing to n, a pair (t,p) is defined to be a positive subset sum if there exists a nonempty subset of p summing to t.
%H A284640 Robert Price, <a href="/A284640/b284640.txt">Table of n, a(n) for n = 1..80</a>
%e A284640 The a(6)=13 subset sums are:
%e A284640 (6,6),
%e A284640 (1,51), (5,51), (6,51),
%e A284640 (2,42), (4,42), (6,42),
%e A284640 (1,321), (2,321), (3,321), (4,321), (5,321), (6,321).
%t A284640 nn=25;Total/@Table[Function[ptn,Length[Union[Total/@Rest[Subsets[ptn]]]]]/@Select[IntegerPartitions[n],UnsameQ@@#&],{n,nn}]
%Y A284640 Cf. A122768, A275972, A276024.
%K A284640 nonn
%O A284640 1,3
%A A284640 _Gus Wiseman_, Mar 31 2017