0,1

The sequence can be also computed with a recurrence that does not explicitly refer to Fibonacci numbers. See the given Maple and C programs.

Conjecture: For n>=1, each term a(n), when considered as a GF(2)[X]-polynomial, is divisible by GF(2)[X] -polynomial (x^3 + 1) ^ A000225(n-1). If this holds, then for n>=1, a(n) = A048720bi(A136380(n),A048723bi(9,A000225(n-1))). Conjecture 2: there is also one extra (x^1 + 1) factor present, see A136384.

A. Karttunen, Table of n, a(n) for n = 0..10

A. Karttunen, C program for computing this sequence

a(n) = Sum_{k=0..A007283(n)-1} ([A000045(k)/(2^n)] mod 2) * 2^k, where [] stands for floor function, i.e. Sum (bit n of Fibonacci(k))*(2^k), k = 0 ... (3*(2^n))-1.

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)

it can be seen that the bits in the nth column from right repeat after a period of A007283(n): 3, 6, 12, 24, ... (See also A001175). This sequence is formed from those bits: 011, reversed is 110, is binary for 6, thus a(0) = 6. 000110, reversed is 11000, is binary for 24, thus a(1) = 24, 000001011010, reversed is 10110100000, is binary for 1440, thus a(2) = 1440.

A036284:=proc(n) option remember; local a, b, c, i, j, k, l, s, x, y, z; if (0 = n) then (6) else a := 0; b := 0; s := 0; x := 0; y := 0; k := 3*(2^(n-1)); l := 3*(2^n); j := 0; for i from 0 to l do z := bit_i(A036284(n-1), (j)); c := (a + b + (`if`((x = y), x, (z+1))) mod 2); if(c <> 0) then s := s + (2^i); fi; a := b; b := c; x := y; y := z; j := j + 1; if(j = k) then j := 0; fi; od; RETURN(s); fi; end:

bit_i := (x, i) -> `mod`(floor(x/(2^i)), 2);

Same sequence in octal base: A036285. Bits reversed: A036286. See also A136378, A136379, A136380, A136382, A136384, A037096, A037093, A000045.

Sequence in context: A128614 A139240 A052524 this_sequence A139235 A136606 A074096

Adjacent sequences: A036281 A036282 A036283 this_sequence A036285 A036286 A036287

nonn,base

Antti Karttunen (His_Firstname.His_Surname(AT)gmail.com), Nov 01 1998. Entry revised Dec 29 2007.