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 A339451 Gray-code-like sequence in which, at each step, the least significant bit that has never been toggled from the previous value, is toggled. 1
 0, 1, 0, 2, 3, 2, 0, 4, 5, 4, 6, 7, 6, 4, 0, 8, 9, 8, 10, 11, 10, 8, 12, 13, 12, 14, 15, 14, 12, 8, 0, 16, 17, 16, 18, 19, 18, 16, 20, 21, 20, 22, 23, 22, 20, 16, 24, 25, 24, 26, 27, 26, 24, 28, 29, 28, 30, 31, 30, 28, 24, 16, 0, 32, 33, 32, 34, 35, 34, 32, 36 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 COMMENTS Conjectured connections: the position of the bit that is toggled to derive a(n) from a(n-1) is A215020(n); the sequence of absolute differences of this sequence is A182105; there is some underlying connection to the "skew binary" counting system. LINKS Alois P. Heinz, Table of n, a(n) for n = 0..65535 EXAMPLE For n = 18, a(n-1) = 8. That is the second 8 in the sequence. We cannot toggle the 1-bit, because that was already used to derive a(16) = 9 from a(15) = 8, so instead we toggle the 2-bit, yielding a(n) = 10. MAPLE a:= proc() local b, a; b:= proc() 1/2 end; a:= proc(n) option remember; local h; if n=0 then 0 else h:= a(n-1); b(h):= 2*b(h); Bits[Xor](h, b(h)) fi end end(): seq(a(n), n=0..127); # Alois P. Heinz, Dec 05 2020 MATHEMATICA a[m_] := Module[{b, a}, b[_] = 1/2; a[n_] := a[n] = Module[{h}, If[n == 0 , 0 , h = a[n - 1]; b[h] = 2*b[h]; BitXor[h, b[h]]]]; a[m]]; Table[a[n], {n, 0, 127}] (* Jean-François Alcover, May 15 2022, after Alois P. Heinz *) CROSSREFS Cf. A182105, A215020. Sequence in context: A307688 A056888 A286297 * A111182 A178142 A076427 Adjacent sequences: A339448 A339449 A339450 * A339452 A339453 A339454 KEYWORD easy,nonn AUTHOR Allan C. Wechsler, Dec 05 2020 STATUS approved

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Last modified June 10 03:15 EDT 2023. Contains 363186 sequences. (Running on oeis4.)