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A261185 Flowsnake parity pattern: a(n) = (A261180(n) mod 2). 3
0, 1, 1, 0, 0, 0, 1, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 1, 0, 1, 1, 0, 0, 0, 1, 0, 1, 1, 0, 0, 0, 1, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 1, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET
1
COMMENTS
This sequence is limit-periodic, thus it is somewhat similar to the Dragon Sequence A014577. Compare g.f. defining relations.
LINKS
FORMULA
G.f. g(x) satisfies g(x) = x^(-3)*g(x^7) + (x^2 + x^3 + x^7)/(1 - x^7).
From Kevin Ryde, Oct 15 2022: (Start)
Fixed point of the morphism 0 -> 0,1,1,0,0,0,1, 1 -> 0,1,1,1,0,0,1 starting from 0.
a(n) = 1 iff n-1 written in base 7 has its least significant non-3 digit equal to 1 or 2 or 6.
(End)
MATHEMATICA
a[x_ /; IntegerQ[(x + 3)/7]] := a[(x + 3)/7]; MapThread[(a[x_ /; IntegerQ[(x - #1)/7]] := #2) &, {{1, 2, 3, 5, 6, 7}, {0, 1, 1, 0, 0, 1}}]; a /@ Range[7^2]
PROG
(PARI) a(n) = n--; my(r); until(r!=3, [n, r]=divrem(n, 7)); bittest(70, r); \\ Kevin Ryde, Oct 15 2022
CROSSREFS
Cf. A261180 (flowsnake directions), A007093 (base 7).
Sequence in context: A359820 A241979 A200244 * A093692 A254114 A105384
KEYWORD
nonn,easy
AUTHOR
Bradley Klee, Aug 11 2015
STATUS
approved

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Last modified March 28 17:42 EDT 2024. Contains 371254 sequences. (Running on oeis4.)