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.

A265161 Array A read by upward antidiagonals in which the entry in row n and column k is defined by A(n,k) = (3/2)*(3^k - 1) + A265159(n,k), n,k >= 1.

Original entry on oeis.org

8, 35, 26, 89, 107, 80, 116, 269, 323, 242, 251, 350, 809, 971, 728, 278, 755, 1052, 2429, 2915, 2186, 332, 836, 2267, 3158, 7289, 8747, 6560, 359, 998, 2510, 6803, 9476, 21869, 26243, 19682, 737, 1079, 2996, 7532, 20411, 28430, 65609, 78731, 59048
Offset: 1

Views

Author

L. Edson Jeffery, Dec 03 2015

Keywords

Comments

Conjecture 1: The array contains without duplication all possible "gap numbers" as defined in A265100.

Examples

			Array A begins:
.      8    26    80    242    728    2186    6560    19682    59048
.     35   107   323    971   2915    8747   26243    78731   236195
.     89   269   809   2429   7289   21869   65609   196829   590489
.    116   350  1052   3158   9476   28430   85292   255878   767636
.    251   755  2267   6803  20411   61235  183707   551123  1653371
.    278   836  2510   7532  22598   67796  203390   610172  1830518
.    332   998  2996   8990  26972   80918  242756   728270  2184812
.    359  1079  3239   9719  29159   87479  262439   787319  2361959
.    737  2213  6641  19925  59777  179333  538001  1614005  4842017
		

Crossrefs

Programs

  • Mathematica
    (* Array: *)
    a005836[1] := 0; a005836[n_] := If[OddQ[n], 3*a005836[Floor[(n + 1)/2]], a005836[n - 1] + 1]; a265159[n_, k_] := 5 + 9*a005836[2^(k - 1)*(2 n - 1)]; a265161[n_, k_] := (3/2)*(3^k - 1) + a265159[n, k]; Grid[Table[a265161[n, k], {n, 9}, {k, 9}]]
    (* Array antidiagonal flattened: *)
    a005836[1] := 0; a005836[n_] := If[OddQ[n], 3*a005836[Floor[(n + 1)/2]], a005836[n - 1] + 1]; a265159[n_, k_] := 5 + 9*a005836[2^(k - 1)*(2 n - 1)]; a265161[n_, k_] := (3/2)*(3^k - 1) + a265159[n, k]; Flatten[Table[a265161[n - k + 1, k], {n, 9}, {k, n}]]

Formula

Conjecture 2: A(n,k) = A191107(n)*3^k - 1.