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.
X:= proc(a,b) local A,B,C; A:= convert(a,base,2); B:= convert(b,base,2); C:= expand(add(A[i]*x^(i-1),i=1..nops(A))*add(B[i]*x^(i-1),i=1..nops(B))) mod 2; eval(C,x=2) end proc: select(t -> 19*t = X(55,t), [$0..10^4]); # Robert Israel, Apr 08 2018
X[a_, b_] := Module[{A, B, C},
A = Reverse@IntegerDigits[a, 2];
B = Reverse@IntegerDigits[b, 2];
C = Expand[
Sum[A[[i]]*x^(i-1), {i, 1, Length[A]}]*
Sum[B[[i]]*x^(i-1), {i, 1, Length[B]}]];
PolynomialMod[C, 2] /. x -> 2];
Select[Range[0, 10^4], 19*# == 55~X~#&] (* Jean-François Alcover, Jan 04 2022, after Robert Israel *)
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