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 A099890 #15 Aug 11 2024 16:46:27
%S A099890 1,2,4,0,8,0,0,0,16,0,0,0,0,0,0,0,32,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,64,
%T A099890 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,128
%N A099890 XOR BINOMIAL transform of the odd numbers; also the main diagonal of the XOR difference triangle A099889.
%H A099890 Harvey P. Dale, <a href="/A099890/b099890.txt">Table of n, a(n) for n = 0..1024</a>
%F A099890 a(0) = 1; a(2^n) = 2^(n+1); a(n) = 0 otherwise.
%t A099890 Join[{1},Table[If[IntegerQ[Log2[n]],2n,0],{n,512}]] (* or *) Join[{1},With[{kk=10},Flatten[ Riffle[ 2^Range[kk],Table[PadRight[{},2^k-1,0],{k,0,kk}]]]]] (* _Harvey P. Dale_, Aug 11 2024 *)
%o A099890 (PARI) a(n)=local(B);B=0;for(i=0,n,B=bitxor(B,binomial(n,i)%2*(2*(n-i)+1)));B
%Y A099890 Cf. A099884, A099889.
%K A099890 nonn
%O A099890 0,2
%A A099890 _Paul D. Hanna_, Oct 29 2004