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.
When Fibonacci numbers are written in binary (see A004685), under each other as: 0000000 (0) 0000001 (1) 0000001 (1) 0000010 (2) 0000011 (3) 0000101 (5) 0001000 (8) 0001101 (13) 0010101 (21) 0100010 (34) 0110111 (55) 1011001 (89) and one starts collecting their bits from column-0 to SW-direction (from the least to the most significant end), one gets 000... (0), ...00001 (1), ...00011 (3), ...001110 (14), etc. (See A102370 for similar transformation done on nonnegative integers).
When powers of 3 are written in binary (see A004656), under each other as: 000000000001 (1) 000000000011 (3) 000000001001 (9) 000000011011 (27) 000001010001 (81) 000011110011 (243) 001011011001 (729) 100010001011 (2187) and one collects their bits from the column-0 to NW-direction (from the least to the most significant end), one gets 1 (1), 01 (1), 011 (3), 0001 (1), 00011 (3), 001001 (9), etc. (See A105033 for similar transformation done on nonnegative integers, A001477).
A037095:= n-> add(bit_n(3^(n-i), i)*(2^i), i=0..n): bit_n := (x, n) -> `mod`(floor(x/(2^n)), 2): seq(A037095(n), n=0..41); # second Maple program: b:= proc(n) option remember; `if`(n=0, 1, (p-> expand((p-(p mod 2))*x/2)+3^n)(b(n-1))) end: a:= n-> subs(x=2, b(n) mod 2): seq(a(n), n=0..42); # Alois P. Heinz, Dec 10 2020
A339601(n) = { my(m=1, s=0); while(n>=m, s += bitand(m,n); m <<= 1; n \= 3); (s); }; A037095(n) = A339601(3^n); \\ Antti Karttunen, Dec 09 2020
BINSLOPE(f) = n -> sum(i=0,n,bitand(2^(n-i),f(i))); \\ General transformation for these kinds of sequences. A037095 = BINSLOPE(n -> 3^n); \\ And its application to A000244. - Antti Karttunen, Dec 09 2020