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 1-6 of 6 results.

A165403 The positions of zeros in A163898 and A163899.

Original entry on oeis.org

0, 1, 10, 21, 28, 136, 171, 190, 300, 325, 406, 465, 496, 2080, 2211, 2278, 2628, 2701, 2926, 3081, 3160, 4656, 4753, 5050, 5253, 5356, 6328, 6555, 6670, 7260, 7381, 7750, 8001, 8128, 32896, 33411, 33670, 34980, 35245, 36046, 36585, 36856
Offset: 0

Views

Author

Antti Karttunen, Sep 19 2009

Keywords

Comments

Equivalently, the positions of ones in A163904.

Crossrefs

These positions are all in the top row of the said arrays, that is, for all n, A002262(a(n)) = 0. A025581(a(n)) gives A165404.

A165404 The positions of zeros in the top row of A163898 (and A163899).

Original entry on oeis.org

0, 1, 4, 6, 7, 16, 18, 19, 24, 25, 28, 30, 31, 64, 66, 67, 72, 73, 76, 78, 79, 96, 97, 100, 102, 103, 112, 114, 115, 120, 121, 124, 126, 127, 256, 258, 259, 264, 265, 268, 270, 271, 288, 289, 292, 294, 295, 304, 306, 307, 312, 313, 316, 318, 319, 384, 385, 388
Offset: 0

Views

Author

Antti Karttunen, Sep 19 2009

Keywords

Comments

Equivalently, the positions of ones in the top row of A163904.

Crossrefs

a(n) = A025581(A165403(n)). Same sequence in binary: A165406. For n>0, A147600(n-1) seems to give the number of terms with binary width n. See also A163901.

A163357 Hilbert curve in N X N grid, starting rightwards from the top-left corner, listed by descending antidiagonals.

Original entry on oeis.org

0, 1, 3, 14, 2, 4, 15, 13, 7, 5, 16, 12, 8, 6, 58, 19, 17, 11, 9, 57, 59, 20, 18, 30, 10, 54, 56, 60, 21, 23, 29, 31, 53, 55, 61, 63, 234, 22, 24, 28, 32, 52, 50, 62, 64, 235, 233, 25, 27, 35, 33, 51, 49, 67, 65, 236, 232, 230, 26, 36, 34, 46, 48, 68, 66, 78, 239, 237, 231
Offset: 0

Views

Author

Antti Karttunen, Jul 29 2009

Keywords

Examples

			The top left 8 X 8 corner of the array shows how this surjective self-avoiding walk begins (connect the terms in numerical order, 0-1-2-3-...):
   0  1 14 15 16 19 20 21
   3  2 13 12 17 18 23 22
   4  7  8 11 30 29 24 25
   5  6  9 10 31 28 27 26
  58 57 54 53 32 35 36 37
  59 56 55 52 33 34 39 38
  60 61 50 51 46 45 40 41
  63 62 49 48 47 44 43 42
		

Crossrefs

Transpose: A163359. Inverse: A163358. One-based version: A163361. Row sums: A163365. Row 0: A163482. Column 0: A163483. Central diagonal: A062880. See also A163334 & A163336 for the Peano curve.

Programs

  • Mathematica
    b[{n_, k_}, {m_}] := (A[k, n] = m-1);
    MapIndexed[b, List @@ HilbertCurve[4][[1]]];
    Table[A[n-k, k], {n, 0, 12}, {k, n, 0, -1}] // Flatten (* Jean-François Alcover, Mar 07 2021 *)

Formula

a(n) = A163355(A054238(n)).

Extensions

Links to further derived sequences added by Antti Karttunen, Sep 21 2009

A163904 Array A(i,j): Cycle size of each A054238(i,j) in permutation A163355, listed antidiagonally as A(0,0), A(0,1), A(1,0), A(0,2), A(1,1), A(2,0), ...

Original entry on oeis.org

1, 1, 2, 6, 2, 6, 3, 3, 6, 3, 1, 6, 6, 3, 4, 3, 3, 3, 6, 8, 8, 1, 3, 4, 3, 4, 4, 2, 1, 2, 2, 2, 2, 2, 2, 2, 6, 2, 4, 4, 4, 4, 8, 2, 6, 6, 6, 2, 4, 4, 8, 8, 4, 6, 6, 12, 6, 12, 2, 4, 8, 4, 4, 12, 6, 18, 6, 6, 12, 6, 2, 4, 8, 4, 6, 12, 18, 6, 3, 12, 18, 6, 9, 2, 2, 8, 6, 6, 12, 18, 3, 3, 6, 18, 18
Offset: 0

Views

Author

Antti Karttunen, Sep 19 2009

Keywords

Examples

			The top left 8x8 corner of this array:
1 1 6 3 1 3 1 1
2 2 3 6 3 3 2 2
6 6 6 3 4 2 4 2
3 3 6 3 2 4 4 2
4 8 4 2 4 4 4 2
8 4 2 4 8 8 4 2
2 2 8 8 4 8 2 2
2 2 4 4 4 8 2 2
		

Crossrefs

a(n) = A163890(A054238(n)) = A163890(A163357(n)). Positions of 1's: A165403. See also A163898, A163899.

A163898 Array A(i,j) giving the square of distance from (i,j) to the location where A054238(i,j) is situated in array A163357(i,j), listed antidiagonally as A(0,0), A(0,1), A(1,0), A(0,2), A(1,1), A(2,0), ...

Original entry on oeis.org

0, 0, 1, 8, 1, 4, 18, 5, 2, 9, 0, 5, 2, 5, 16, 2, 1, 2, 9, 10, 25, 0, 1, 4, 9, 16, 17, 36, 0, 1, 4, 9, 16, 25, 36, 49, 128, 1, 2, 1, 10, 9, 10, 25, 64, 162, 113, 4, 5, 18, 5, 4, 5, 50, 81, 128, 113, 100, 9, 10, 5, 10, 1, 64, 65, 100, 128, 113, 100, 89, 16, 17, 20, 25, 64, 81, 100
Offset: 0

Views

Author

Antti Karttunen, Sep 19 2009

Keywords

Examples

			The top left 8 X 8 corner of this array:
   0  0  8 18  0  2  0  0
   1  1  5  5  1  1  1  1
   4  2  2  2  4  4  2  4
   9  5  9  9  9  1  5  9
  16 10 16 16 10 18 10 16
  25 17 25  9  5  5 17 25
  36 36 10  4 10 20 36 36
  49 25  5  1 25 29 25 49
		

Crossrefs

a(n) = A163900(A054238(n)). Positions of zeros: A165403. See also A163899, A163904.

A163900 Squared distance between n's location in A054238 array and A163357 array.

Original entry on oeis.org

0, 0, 1, 1, 8, 18, 5, 5, 4, 2, 9, 5, 2, 2, 9, 9, 0, 2, 1, 1, 0, 0, 1, 1, 4, 4, 9, 1, 2, 4, 5, 9, 16, 10, 25, 17, 16, 16, 25, 9, 36, 36, 49, 25, 10, 4, 5, 1, 10, 18, 5, 5, 10, 16, 17, 25, 10, 20, 25, 29, 36, 36, 25, 49, 128, 162, 113, 113, 128, 128, 113, 145, 100, 100, 89, 113, 162
Offset: 0

Views

Author

Antti Karttunen, Sep 19 2009

Keywords

Crossrefs

Positions of zeros: A163901. See also A163898, A163899.

Formula

a(n) = A000290(abs(A059906(n)-A059252(n))) + A000290(abs(A059905(n)-A059253(n))).
Showing 1-6 of 6 results.