cp's OEIS Frontend

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.

Showing 1-3 of 3 results.

A163542 The relative direction (0=straight ahead, 1=turn right, 2=turn left) taken by the type I Hilbert's Hamiltonian walk A163357 at the step n.

Original entry on oeis.org

1, 1, 2, 0, 2, 2, 1, 1, 2, 2, 0, 2, 1, 1, 0, 1, 2, 2, 1, 0, 1, 1, 2, 2, 1, 1, 0, 1, 2, 2, 0, 0, 2, 2, 1, 0, 1, 1, 2, 2, 1, 1, 0, 1, 2, 2, 1, 0, 1, 1, 2, 0, 2, 2, 1, 1, 2, 2, 0, 2, 1, 1, 2, 0, 2, 2, 1, 0, 1, 1, 2, 2, 1, 1, 0, 1, 2, 2, 0, 2, 1, 1, 2, 0, 2, 2, 1, 1, 2, 2, 0, 2, 1, 1, 0, 0, 1, 1, 2, 0, 2, 2
Offset: 1

Views

Author

Antti Karttunen, Aug 01 2009

Keywords

Comments

a(16*n) = a(256*n) for all n.

Crossrefs

a(n) = A014681(A163543(n)). See also A163540.

Programs

  • Mathematica
    HC = {L[n_ /; IntegerQ[n/2]] :> {F[n], L[n], L[n + 1], R[n + 2]},
       R[n_ /; IntegerQ[(n + 1)/2]] :> {F[n], R[n], R[n + 3], L[n + 2]},
       R[n_ /; IntegerQ[n/2]] :> {L[n], R[n + 1], R[n], F[n + 3]},
       L[n_ /; IntegerQ[(n + 1)/2]] :> {R[n], L[n + 3], L[n], F[n + 1]},
       F[n_ /; IntegerQ[n/2]] :> {L[n], R[n + 1], R[n], L[n + 3]},
       F[n_ /; IntegerQ[(n + 1)/2]] :> {R[n], L[n + 3], L[n], R[n + 1]}};
    a[1] = L[0]; Map[(a[n_ /; IntegerQ[(n - #)/16]] :=
        Part[Flatten[a[(n + 16 - #)/16] /. HC /. HC], #]) &, Range[16]];
    Part[a[#] & /@ Range[4^4] /. {L[] -> 2, R[] -> 1, F[_] -> 0},
    2 ;; -1] (* Bradley Klee, Aug 07 2015 *)
  • Scheme
    (define (A163542 n) (A163241 (modulo (- (A163540 (1+ n)) (A163540 n)) 4)))

Formula

a(n) = A163241((A163540(n+1)-A163540(n)) modulo 4).

A163539 The change in Y-coordinate when moving from the n-1:th to the n-th term in the type I Hilbert's Hamiltonian walk A163357.

Original entry on oeis.org

0, 0, 1, 0, 1, 1, 0, -1, 0, 1, 0, -1, -1, 0, -1, 0, 0, 1, 0, -1, 0, 0, 1, 0, 1, 0, 1, 0, 0, -1, 0, 1, 1, 1, 0, -1, 0, 0, 1, 0, 1, 0, 1, 0, 0, -1, 0, 1, 0, 0, -1, 0, -1, -1, 0, 1, 0, -1, 0, 1, 1, 0, 1, 0, 1, 1, 0, -1, 0, 0, 1, 0, 1, 0, 1, 0, 0, -1, 0, 1, 1, 0, 1, 0, 1, 1, 0, -1, 0, 1, 0, -1, -1, 0
Offset: 0

Views

Author

Antti Karttunen, Aug 01 2009

Keywords

Crossrefs

These are the first differences of A059252. See also: A163538, A163541, A163543.

Formula

a(0)=0, a(n) = A059252(n) - A059252(n-1).

A163541 The absolute direction (0=east, 1=south, 2=west, 3=north) taken by the type I Hilbert's Hamiltonian walk A163359 at the step n.

Original entry on oeis.org

1, 0, 3, 0, 0, 1, 2, 1, 0, 1, 2, 2, 3, 2, 1, 1, 0, 1, 2, 1, 1, 0, 3, 0, 1, 0, 3, 3, 2, 3, 0, 0, 0, 1, 2, 1, 1, 0, 3, 0, 1, 0, 3, 3, 2, 3, 0, 3, 3, 2, 1, 2, 2, 3, 0, 3, 2, 3, 0, 0, 1, 0, 3, 0, 0, 1, 2, 1, 1, 0, 3, 0, 1, 0, 3, 3, 2, 3, 0, 0, 1, 0, 3, 0, 0, 1, 2, 1, 0, 1, 2, 2, 3, 2, 1, 1, 1, 0, 3, 0, 0, 1
Offset: 1

Views

Author

Antti Karttunen, Aug 01 2009

Keywords

Comments

Taking every sixteenth term gives the same sequence: (and similarly for all higher powers of 16 as well): a(n) = a(16*n).

Crossrefs

a(n) = A163541(A008598(n)) = A004442(A163540(n)). See also A163543.

Programs

  • Mathematica
    HC = {L[n_ /; IntegerQ[n/2]] :> {F[n], L[n], L[n + 1], R[n + 2]},
    R[n_ /; IntegerQ[(n + 1)/2]] :> {F[n], R[n], R[n + 3], L[n + 2]},
    R[n_ /; IntegerQ[n/2]] :> {L[n], R[n + 1], R[n], F[n + 3]},
    L[n_ /; IntegerQ[(n + 1)/2]] :> {R[n], L[n + 3], L[n], F[n + 1]},
    F[n_ /; IntegerQ[n/2]] :> {L[n], R[n + 1], R[n], L[n + 3]},
    F[n_ /; IntegerQ[(n + 1)/2]] :> {R[n], L[n + 3], L[n], R[n + 1]}};
    a[1] = L[0]; Map[(a[n_ /; IntegerQ[(n - #)/16]] := Part[Flatten[a[(n + 16 - #)/16]/.HC/.HC],#]) &, Range[16]];
    Part[FoldList[Mod[Plus[#1, #2], 4] &, 0, a[#] & /@ Range[4^4]/.{F[n_]:>0,L[n_]:>1,R[n_]:>-1}], 2 ;; -1] (* Bradley Klee, Aug 07 2015 *)
  • Scheme
    (define (A163541 n) (modulo (+ 3 (A163538 n) (A163539 n) (abs (A163538 n))) 4))

Formula

a(n) = A010873(A163538(n) + A163539(n) + abs(A163538(n)) + 3).
Showing 1-3 of 3 results.