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A332384
a(n) is the Y-coordinate of the n-th point of the dragon curve. Sequence A332383 gives X-coordinates.
5
0, 0, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 0, 0, -1, -1, 0, 0, -1, -1, -2, -2, -1, -1, -2, -2, -3, -3, -4, -4, -5, -5, -4, -4, -5, -5, -6, -6, -5, -5, -6, -6, -5, -5, -4, -4, -3, -3, -4, -4, -5, -5, -6, -6, -5, -5, -6, -6, -7, -7, -8, -8, -9, -9, -8, -8, -9, -9, -10
OFFSET
0,5
FORMULA
For any k >= 0:
- a(2^(4*k)) = 0,
- a(2^(4*k+1)) = (-4)^k,
- a(2^(4*k+2)) = 2*(-4)^k,
- a(2^(4*k+3)) = 2*(-4)^k.
MATHEMATICA
Im[Join[{0}, Accumulate[Nest[Join[#, Reverse[I #]] &, {1}, 7]]]] (* Vladimir Reshetnikov, Apr 14 2022 *)
PROG
(PARI) A014577(n)=1/2*(1+(-1)^(1/2*((n+1)/2^valuation(n+1, 2)-1)))
{ z=0; d=1; for (n=0, 68, print1 (imag(z) ", "); z += d; d*=if (A014577(n), +I, -I)) }
CROSSREFS
Cf. A014577, A332383 (X-coordinates and additional comments).
Sequence in context: A290320 A348761 A318703 * A275885 A199010 A286944
KEYWORD
sign,base
AUTHOR
Rémy Sigrist, Feb 10 2020
STATUS
approved