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.

A160796 Total number of "ON" cells at n-th stage in simple 2-dimensional cellular automaton which is the "corner" structure corresponding to A160118.

Original entry on oeis.org

0, 1, 8, 11, 32, 35, 56, 65, 128, 131, 152, 161, 224, 233, 296, 323, 512, 515, 536, 545, 608, 617, 680, 707, 896, 905, 968, 995, 1184, 1211, 1400, 1481, 2048, 2051, 2072, 2081, 2144, 2153, 2216, 2243, 2432, 2441, 2504, 2531, 2720, 2747, 2936, 3017, 3584, 3593, 3656
Offset: 0

Views

Author

Omar E. Pol, Jun 13 2009, Jun 14 2009

Keywords

Comments

This bears the same relationship to A160118 as A153006 does to A139250.

Examples

			If we label the generations of cells turned ON by consecutive numbers we get the cell pattern shown below:
..9...............9
...888.888.888.888.
...878.878.878.878.
...8866688.8866688.
.....656.....656...
...8866444.4446688.
...878.434.434.878.
...888.4422244.888.
.........212.......
00000000002244.888.
0000000000.434.878.
0000000000.4446688.
0000000000...656...
0000000000.8866688.
0000000000.878.878.
0000000000.888.888.
0000000000........9
0000000000.........
0000000000.........
		

Crossrefs

Programs

  • Mathematica
    With[{d = 2}, wt[n_] := DigitCount[n, 2, 1]; a[n_] := (5 + 3 * If[OddQ[n], 3^d + (2^d)*Sum[(2^d - 1)^(wt[k] - 1), {k, 1, (n - 1)/2}] + (2^d)*(3^d - 2)*Sum[(2^d - 1)^(wt[k] - 1), {k, 1, (n - 3)/2}], 3^d + (2^d)*Sum[(2^d - 1)^(wt[k] - 1), {k, 1, n/2 - 1}] + (2^d)*(3^d - 2)*Sum[(2^d - 1)^(wt[k] - 1), {k, 1, n/2 - 1}]]) / 4; a[0] = 0; a[1] = 1; Array[a, 50, 0]] (* Amiram Eldar, Aug 01 2023 *)

Formula

a(n) = 2 + (3/4)*(A160118(n) - 1) if n >= 2.

Extensions

Entry revised by Omar E. Pol and N. J. A. Sloane, Feb 16 2010
More terms from Nathaniel Johnston, Nov 13 2010
Corrected by Sean A. Irvine, Mar 23 2011, in response to correction to A160118
More terms from Amiram Eldar, Aug 01 2023