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 A101121 #11 Jul 10 2022 13:23:50
%S A101121 7,17,34,68,159,257,514,1028,2063,4097,8194,16388,32831,65537,131074,
%T A101121 262148,524303,1048577,2097154,4194308,8388639,16777217,33554434,
%U A101121 67108868,134217743,268435457,536870914,1073741828,2147483775
%N A101121 Bitwise XOR of adjacent terms of A101120; also the nonzero terms of A101122.
%C A101121 A101120 gives the records in A101119, which equals the nonzero differences of A006519 and A003484. A101122 is the XOR BINOMIAL transform of A101119 and has zeros everywhere except at positions equal to powers of 2.
%F A101121 a(n) = A101120(n-1) XOR A101120(n) for n>1, with a(1) = A101120(1), where A101120(n) = 2^(n+3) - 2^((n-1)(Mod 4)) - 8*floor((n+3)/4).
%e A101121 a(5) = 159 since A101120(4)=112, A101120(5)=239 and 159 = 112 XOR 239.
%o A101121 (PARI) {a(n)=bitxor(2^(n+2)-2^((n-2)%4)-8*((n+2)\4),2^(n+3)-2^((n-1)%4)-8*((n+3)\4))}
%o A101121 (Python)
%o A101121 def A101121(n): return ((1<<(n+2))-(1<<((n-2)&3))-(((n+2)&-4)<<1))^((1<<(n+3))-(1<<((n-1)&3))-(((n+3)&-4)<<1)) # _Chai Wah Wu_, Jul 10 2022
%Y A101121 Cf. A003484, A006519, A101119, A101120, A101122.
%K A101121 nonn
%O A101121 1,1
%A A101121 _Simon Plouffe_ and _Paul D. Hanna_, Dec 02 2004