Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
%I #5 May 27 2020 01:57:30
%S 0,1,2,3,4,5,6,7,8,9,14,15,16,17,18,19,28,29,30,31,32,33,36,37,58,59,
%T 62,63,64,65,66,67,72,73,74,75,116,117,118,119,124,125,126,127,128,
%U 129,134,135,146,147,148,149,234,235,236,237,248,249,254,255,256
%N Fixed points of A335133.
%C The EQ-triangles generated from the binary expansion of the terms of this sequence have reflection symmetry through axis U-U:
%C . U
%C . .___________
%C . \ . /
%C . \ . /
%C . \ .
%C . \ / .
%C . \ / U
%C . v
%H Rémy Sigrist, <a href="/A335134/a335134.png">Illustration of initial terms</a>
%e A335133(28) = 28, so 28 belongs to this sequence.
%o (PARI) is(n) = {
%o my (b=binary(n), v=0);
%o forstep (x=#b-1, 0, -1,
%o if (b[1], v+=2^x);
%o b=vector(#b-1, k, b[k]==b[k+1])
%o );
%o v==n
%o }
%Y Cf. A335133.
%K nonn,base
%O 1,3
%A _Rémy Sigrist_, May 24 2020