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 A212352 #11 Apr 18 2023 09:42:40 %S A212352 0,1,3,9,25,75,235,759,2521,8555,29503,103129,364547,1300819,4679471, %T A212352 16952161,61790441,226451035,833918839,3084255127,11451630043, %U A212352 42669225171,159497648599,597950875255,2247724108771,8470205600639 %N A212352 Row sums of A047997. %C A212352 Also the number of nonempty subsets of {1..2n} with mean n, even bisection of A362046. - _Gus Wiseman_, Apr 15 2023 %F A212352 From _Gus Wiseman_, Apr 15 2023: (Start) %F A212352 a(n) = A000980(n)/2 - 1. %F A212352 a(n) = A047653(n) - 1. %F A212352 a(n) = A133406(2n+1) - 1. %F A212352 a(n) = A362046(2n). %F A212352 (End) %e A212352 From _Gus Wiseman_, Apr 15 2023: (Start) %e A212352 The a(1) = 1 through a(3) = 9 subsets: %e A212352 {1} {2} {3} %e A212352 {1,3} {1,5} %e A212352 {1,2,3} {2,4} %e A212352 {1,2,6} %e A212352 {1,3,5} %e A212352 {2,3,4} %e A212352 {1,2,3,6} %e A212352 {1,2,4,5} %e A212352 {1,2,3,4,5} %e A212352 (End) %t A212352 Table[Length[Select[Subsets[Range[2n]],Mean[#]==n&]],{n,0,6}] (* _Gus Wiseman_, Apr 15 2023 *) %Y A212352 Equals A047653(n) - 1. %Y A212352 Row sums of A047997. %Y A212352 For median instead of mean we have A079309, bisection of A361801. %Y A212352 Even bisection of A362046, zero-based version A070925. %Y A212352 A000980 counts nonempty subsets of {1..2n-1} with mean n. %Y A212352 A007318 counts subsets by length. %Y A212352 A327475 counts subsets with integer mean. %Y A212352 A327481 counts subsets by mean. %Y A212352 Cf. A000975, A013580, A024718, A057552, A133406, A361866. %K A212352 nonn %O A212352 0,3 %A A212352 _N. J. A. Sloane_, May 16 2012