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 1-2 of 2 results.

A328696 Rectangular array R read by descending antidiagonals: apply x -> (x+1)/2 to each odd term of the Wythoff array (A035513), and delete all others.

Original entry on oeis.org

1, 2, 4, 3, 6, 5, 7, 15, 8, 12, 11, 24, 20, 19, 9, 28, 62, 32, 49, 23, 10, 45, 100, 83, 79, 37, 16, 13, 117, 261, 134, 206, 96, 41, 21, 14, 189, 422, 350, 333, 155, 66, 54, 36, 25, 494, 1104, 566, 871, 405, 172, 87, 58, 40, 17, 799, 1786, 1481, 1409, 655
Offset: 1

Views

Author

Clark Kimberling, Oct 26 2019

Keywords

Comments

Every positive integer occurs exactly once in R, and every row of R is a linear recurrence sequence.

Examples

			Row 1 of the Wythoff array is (1,2,3,5,8,13,21,34,55,89,144,...), so that row 1 of R is (1,2,3,7,11,...) = A107857 (essentially).
_______________
Northwest corner of R:
   1,  2,  3,  7,  11,  28,  45,  117,  189,  494,   799
   4,  6, 15, 24,  62, 100, 261,  422, 1104, 1786,  4675
   5,  8, 20, 32,  83, 134, 350,  566, 1481, 2396,  6272
  12, 19, 49, 79, 206, 333, 871, 1409, 3688, 5967, 15621
   9, 23, 37, 96, 155, 405, 655, 1714, 2773, 7259, 11745
  10, 16, 41, 66, 172, 278, 727, 1176, 3078, 4980, 13037
  13, 21, 54, 87, 227, 367, 960, 1553, 4065, 6577, 17218
		

Crossrefs

Programs

  • Mathematica
    w[n_, k_] := Fibonacci[k + 1] Floor[n*GoldenRatio] + (n - 1) Fibonacci[k];
    Table[w[n - k + 1, k], {n, 12}, {k, n, 1, -1}] // Flatten;
    q[n_, k_] := If[Mod[w[n, k], 2] == 1, (1 + w[n, k])/2, 0];
    t[n_] := Union[Table[q[n, k], {k, 1, 50}]];
    u[n_] := If[First[t[n]] == 0, Rest[t[n]], t[n]]
    s = Select[Range[40], ! u[#] == {} &]; u1[n_] := u[s[[n]]];
    Column[Table[u1[n], {n, 1, 10}]] (* A328696 array *)
    v[n_, k_] := u1[n][[k]];
    Table[v[n - k + 1, k], {n, 12}, {k, n, 1, -1}] // Flatten (* A328696 sequence *)

A328697 Rectangular array R read by descending antidiagonals: divide the multiples of 3 in the Wythoff array (A035513) by 3, and delete all others.

Original entry on oeis.org

1, 7, 6, 48, 41, 2, 329, 281, 14, 3, 2255, 1926, 96, 5, 4, 15456, 13201, 658, 8, 28, 20, 105937, 90481, 4510, 13, 192, 137, 15, 726103, 620166, 30912, 21, 1316, 939, 103, 27, 4976784, 4250681, 211874, 34, 9020, 6436, 706, 185, 12, 34111385, 29134601, 1452206
Offset: 1

Views

Author

Clark Kimberling, Oct 29 2019

Keywords

Comments

Every positive integer occurs in R exactly once, and every row of R is a linear recurrence sequence.
Row 1 of R is essentially A004187.
Row 2 of R is essentially A049685.
Row 4 of R is essentially A000045.

Examples

			Row 1 of the Wythoff array is (1,2,3,5,8,13,21,34,55,89,144,...), so that row 1 of R is (1,7,48,329,2255,...).
=====================
Northwest corner of R:
   1,   7,  48,  329,  2255,  15456,  105937,   726103
   6,  41, 281, 1926, 13201,  90481,  620166,  4250681
   2,  14,  96,  658,  4510,  30912,  211874,  1452206
   3,   5,   8,   13,    21,     34,      55,       89
   4,  28, 192, 1316,  9020,  61824,  423748,  2904412
  20, 137, 939, 6436, 44113, 302355, 2072372, 14204249
  15, 103, 706, 4839, 33167, 227330, 1558143, 10679671
		

Crossrefs

Showing 1-2 of 2 results.