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 A133851 #6 Dec 10 2020 20:39:49 %S A133851 1,0,0,4,0,0,16,0,0,64,0,0,256,0,0,1024,0,0,4096,0,0,16384,0,0,65536, %T A133851 0,0,262144,0,0,1048576,0,0,4194304,0,0,16777216,0,0,67108864,0,0, %U A133851 268435456,0,0,1073741824,0,0,4294967296,0,0,17179869184,0,0 %N A133851 Sloping binary representation of powers of 4 (A000302), slope = -1 . %F A133851 a(3n) = A000302(n), a(3n+1) = a(3n+2) = 0. - _Alois P. Heinz_, Dec 10 2020 %e A133851 When powers of 4 are written in binary (see A098608), under each other as: %e A133851 0000000000001 (1) %e A133851 0000000000100 (4) %e A133851 0000000010000 (16) %e A133851 0000001000000 (64) %e A133851 0000100000000 (256) %e A133851 0010000000000 (1024) %e A133851 1000000000000 (4096) %e A133851 and one collects their bits from the column=0 to NW-direction (from the least to the most significant end), one gets 1 (1), 00 (0), 000 (0), 0100 (4), 00000 (0), 000000 (0), 0010000 (16), etc. (see 0105033 for similar transformation done on nonnegative integers) %Y A133851 Cf. A037095, A077957, A105033, A000302, A098608, A102370(sloping binary numbers). %K A133851 base,nonn %O A133851 0,4 %A A133851 _Philippe Deléham_, Jan 06 2008