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 A364672 #12 Jan 28 2024 02:41:12
%S A364672 0,0,0,2,6,18,41,94,198,416,853,1746,3531,7151,14415,29049,58431,
%T A364672 117528,236145,474436,952627,1912494,3838175,7701540,15449676,
%U A364672 30988137,62142415,124600422,249795358,500719994,1003575768,2011211100,4030123185,8074898552,16177657763,32408393211,64917907623
%N A364672 Number of subsets of {1..n} not containing all of their own first differences.
%F A364672 a(n) = 2^n - A364671(n). - _Andrew Howroyd_, Jan 27 2024
%e A364672 The a(0) = 0 through a(5) = 18 subsets:
%e A364672 . . . {1,3} {1,3} {1,3}
%e A364672 {2,3} {1,4} {1,4}
%e A364672 {2,3} {1,5}
%e A364672 {3,4} {2,3}
%e A364672 {1,3,4} {2,5}
%e A364672 {2,3,4} {3,4}
%e A364672 {3,5}
%e A364672 {4,5}
%e A364672 {1,2,5}
%e A364672 {1,3,4}
%e A364672 {1,3,5}
%e A364672 {1,4,5}
%e A364672 {2,3,4}
%e A364672 {2,3,5}
%e A364672 {2,4,5}
%e A364672 {3,4,5}
%e A364672 {1,3,4,5}
%e A364672 {2,3,4,5}
%t A364672 Table[Length[Select[Subsets[Range[n]],!SubsetQ[#,Differences[#]]&]],{n,0,10}]
%Y A364672 For disjunction instead of containment we have A364463, partitions A363260.
%Y A364672 For overlap we have A364466, partitions A364467 (strict A364536).
%Y A364672 The complement is counted by A364671, partitions A364673, A364674, A364675.
%Y A364672 First differences of terms are A364753, complement A364752.
%Y A364672 Cf. A007862, A054519, A151897, A237667, A325325, A326083, A363225, A364345, A364464, A364537.
%K A364672 nonn
%O A364672 0,4
%A A364672 _Gus Wiseman_, Aug 05 2023
%E A364672 a(21) onwards (using A364671) added by _Andrew Howroyd_, Jan 27 2024