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 A365919 #9 Sep 30 2023 09:22:35 %S A365919 1,3,9,21,22,27,63,76,81,117,147,175,186,189,243,248,273,286,290,322, %T A365919 345,351,399,418,441,513,516,567,688,715,729,819,1029,1053,1062,1156, %U A365919 1180,1197,1323,1375,1416,1484,1521,1539,1701,1827,1888,1911,2068,2115,2130 %N A365919 Heinz numbers of integer partitions with the same number of distinct positive subset-sums as distinct non-subset-sums. %C A365919 The Heinz number of a partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k). This gives a bijective correspondence between positive integers and integer partitions. %F A365919 Positive integers k such that A304793(k) = A325799(k). %e A365919 The terms together with their prime indices begin: %e A365919 1: {} %e A365919 3: {2} %e A365919 9: {2,2} %e A365919 21: {2,4} %e A365919 22: {1,5} %e A365919 27: {2,2,2} %e A365919 63: {2,2,4} %e A365919 76: {1,1,8} %e A365919 81: {2,2,2,2} %e A365919 117: {2,2,6} %e A365919 147: {2,4,4} %e A365919 175: {3,3,4} %e A365919 186: {1,2,11} %e A365919 189: {2,2,2,4} %e A365919 243: {2,2,2,2,2} %t A365919 prix[n_]:=If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]]; %t A365919 smu[y_]:=Union[Total/@Rest[Subsets[y]]]; %t A365919 nmz[y_]:=Complement[Range[Total[y]],Total/@Subsets[y]]; %t A365919 Select[Range[100],Length[smu[prix[#]]]==Length[nmz[prix[#]]]&] %Y A365919 The LHS is A304793, counted by A365658, with empty sets A299701. %Y A365919 The RHS is A325799, counted by A365923 (strict A365545). %Y A365919 A046663 counts partitions without a subset summing to k, strict A365663. %Y A365919 A056239 adds up prime indices, row sums of A112798. %Y A365919 A276024 counts positive subset-sums of partitions, strict A284640. %Y A365919 A325781 ranks complete partitions, counted by A126796. %Y A365919 A365830 ranks incomplete partitions, counted by A365924. %Y A365919 A365918 counts non-subset-sums of partitions, strict A365922. %Y A365919 Cf. A001223, A005117, A006827, A073491, A188431, A304792, A365831. %K A365919 nonn %O A365919 1,2 %A A365919 _Gus Wiseman_, Sep 25 2023