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 A099901 #11 Jul 11 2015 01:05:19
%S A099901 1,2,6,14,22,46,118,206,278,558,1654,3790,5910,11310,28790,49358,
%T A099901 65814,131630,394870,921294,1447702,3025966,7762038,13549774,18284822,
%U A099901 36438574,108004982,247467726,385881878,738208814,1879076982,3221274830
%N A099901 Shifts left and divides by 2 under the XOR BINOMIAL transform (A099902).
%C A099901 Equals the XOR BINOMIAL transform of A099902. Also, equals the leftmost column of the XOR difference triangle A099900, in which the central terms of the rows forms the powers of 2.
%F A099901 a(0)=1; a(n) = SumXOR_{k=0..n-1} (C(n-1-k+[k/2], [k/2])mod 2)*2^(k+1) for n>0. a(n) = SumXOR_{i=0..n} (C(n, i)mod 2)*A099902(n-i), where SumXOR is the analog of summation under the binary XOR operation and C(k, i)mod 2 = A047999(k, i).
%o A099901 (PARI) {a(n)=local(B);B=0;if(n==0,B=1, for(k=0,n-1, B=bitxor(B,binomial(n-1-k+k\2,k\2)%2*2^(k+1))));B}
%Y A099901 Cf. A099884, A099900, A099902.
%K A099901 eigen,nonn
%O A099901 0,2
%A A099901 _Paul D. Hanna_, Oct 30 2004