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.

Previous Showing 11-20 of 23 results. Next

A256260 Total number of ON states after n generations of a cellular automaton-like on the square grid.

Original entry on oeis.org

1, 5, 9, 21, 25, 37, 57, 85, 89, 101, 121, 149, 169, 213, 281, 341, 345, 357, 377, 405, 425, 469, 537, 597, 617, 661, 729, 821, 937, 1077, 1241, 1365, 1369, 1381, 1401, 1429, 1449, 1493, 1561, 1621, 1641, 1685, 1753, 1845, 1961, 2101, 2265, 2389, 2409, 2453, 2521, 2613, 2729, 2869, 3033, 3221, 3433, 3669, 3929, 4213, 4521, 4853, 5209, 5461
Offset: 1

Views

Author

Omar E. Pol, Mar 28 2015

Keywords

Comments

First differs from A169707 at a(28).
Compare A169707. It appears that both sequences share infinitely many terms, for example: a(1)..a(27), a(31)..a(43), a(47)..a(51), etc.
See also the conjecture in the Example section.
The main entry for this sequence is A256263.
A256261 gives the number of cells turned ON at n-th stage.

Examples

			Written as an irregular triangle T(j,k), k>=1, in which the row lengths are the terms of A011782, the sequence begins:
1;
5;
9,   21;
25,  37, 57, 85;
89, 101,121,149,169,213,281,341;
345,357,377,405,425,469,537,597,617,661,729,821,937,1077,1241,1365;
...
The right border gives the positive terms of A002450.
It appears that this triangle at least shares with the triangles from the following sequences; A147562, A162795, A169707, A255366, A256250, the positive elements of the columns k, if k is a power of 2.
		

Crossrefs

Formula

a(n) = 1 + 4*A256264(n-1).

A256263 Triangle read by rows: T(j,k) = 2*k-1 if k is a power of 2, otherwise, between positions that are powers of 2 we have the initial terms of A016969, with j>=0, 1<=k<=A011782(j) and T(0,1) = 0.

Original entry on oeis.org

0, 1, 1, 3, 1, 3, 5, 7, 1, 3, 5, 7, 5, 11, 17, 15, 1, 3, 5, 7, 5, 11, 17, 15, 5, 11, 17, 23, 29, 35, 41, 31, 1, 3, 5, 7, 5, 11, 17, 15, 5, 11, 17, 23, 29, 35, 41, 31, 5, 11, 17, 23, 29, 35, 41, 47, 53, 59, 65, 71, 77, 83, 89, 63, 1, 3, 5, 7, 5, 11, 17, 15, 5, 11, 17, 23, 29, 35, 41, 31, 5, 11, 17, 23, 29, 35, 41, 47, 53, 59, 65, 71, 77, 83, 89
Offset: 0

Views

Author

Omar E. Pol, Mar 30 2015

Keywords

Comments

Partial sums give A256264.
First differs from A160552 at a(27).
Appears to be a canonical sequence partially related to the cellular automata of A139250, A147562, A162795, A169707, A255366, A256250. See also A256264 and A256260.

Examples

			Written as an irregular triangle in which the row lengths are the terms of A011782, the sequence begins:
0;
1;
1,3;
1,3,5,7;
1,3,5,7,5,11,17,15;
1,3,5,7,5,11,17,15,5,11,17,23,29,35,41,31;
1,3,5,7,5,11,17,15,5,11,17,23,29,35,41,31,5,11,17,23,29,35,41,47,53,59,65,71,77,83,89,63;
...
Right border gives A000225.
Apart from the initial 0 the row sums give A000302.
Rows converge to A256258.
.
Illustration of initial terms in the fourth quadrant of the square grid:
---------------------------------------------------------------------------
n   a(n)                 Compact diagram
---------------------------------------------------------------------------
0    0     _
1    1    |_|_ _
2    1      |_| |
3    3      |_ _|_ _ _ _
4    1          |_| | | |
5    3          |_ _| | |
6    5          |_ _ _| |
7    7          |_ _ _ _|_ _ _ _ _ _ _ _
8    1                  |_| | | |_ _  | |
9    3                  |_ _| | |_  | | |
10   5                  |_ _ _| | | | | |
11   7                  |_ _ _ _| | | | |
12   5                  | | |_ _ _| | | |
13  11                  | |_ _ _ _ _| | |
14  17                  |_ _ _ _ _ _ _| |
15  15                  |_ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
16   1                                  |_| | | |_ _  | |_ _ _ _ _ _  | |
17   3                                  |_ _| | |_  | | |_ _ _ _ _  | | |
18   5                                  |_ _ _| | | | | |_ _ _ _  | | | |
19   7                                  |_ _ _ _| | | | |_ _ _  | | | | |
20   5                                  | | |_ _ _| | | |_ _  | | | | | |
21  11                                  | |_ _ _ _ _| | |_  | | | | | | |
22  17                                  |_ _ _ _ _ _ _| | | | | | | | | |
23  15                                  |_ _ _ _ _ _ _ _| | | | | | | | |
24   5                                  | | | | | | |_ _ _| | | | | | | |
25  11                                  | | | | | |_ _ _ _ _| | | | | | |
26  17                                  | | | | |_ _ _ _ _ _ _| | | | | |
27  23                                  | | | |_ _ _ _ _ _ _ _ _| | | | |
28  29                                  | | |_ _ _ _ _ _ _ _ _ _ _| | | |
29  35                                  | |_ _ _ _ _ _ _ _ _ _ _ _ _| | |
30  41                                  |_ _ _ _ _ _ _ _ _ _ _ _ _ _ _| |
31  31                                  |_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|
.
a(n) is also the number of cells in the n-th region of the diagram.
A256264(n) gives the total number of cells after n-th stage.
		

Crossrefs

Programs

  • Mathematica
    Flatten@Join[{0}, NestList[Join[#, Range[Length[#] - 1]*6 - 1, {2 #[[-1]] + 1}] &, {1}, 6]] (* Ivan Neretin, Feb 14 2017 *)

Extensions

Terms a(95) to a(98) fixed by Ivan Neretin, Feb 14 2017

A255366 Total number of ON cells at stage n of two-dimensional cellular automaton defined by the rules of the "Ulam-Warburton" two-dimensional cellular automaton (A147562) for two of its wedges and defined by "Rule 750" using the von Neumann neighborhood (A169707) for the two other wedges.

Original entry on oeis.org

1, 5, 9, 21, 25, 37, 53, 85, 89, 101, 117, 149, 165, 205, 257, 341, 345, 357, 373, 405, 421, 461, 513, 597, 613, 653, 705, 797, 857, 989, 1141, 1365, 1369, 1381, 1397, 1429, 1445, 1485, 1537, 1621, 1637, 1677, 1729, 1821, 1881, 2013, 2165, 2389, 2405, 2445, 2497
Offset: 1

Views

Author

Omar E. Pol, Feb 21 2015

Keywords

Comments

First differs from A162795 at a(14), but it appears that then they share infinitely many terms. It appears that this is very close to A162795 rather than both A147562 and A169707.
The graphs of both A162795 and this sequence are intertwined.
Note that there are four main versions of this cellular automaton, depending on whether the wedges with the same rule are opposite or perpendicular and also depending on whether each mentioned version is represented by the "one-step rook" illustration or by the "one-step bishop" illustration. The four versions are represented by this sequence.
a(43) = 1729 is also the Hardy-Ramanujan number.

Examples

			a(43) = (1705 + 1753)/2 = 3458/2 = 1729.
		

Crossrefs

Formula

a(n) = (A147562(n) + A169707(n))/2.
It appears that a(n) = A147562(n) = A162795(n) = A169709(n), if n is a member of A048645, or in other words: if the binary weight of n is 1 or 2, but note that a(n) = A162795(n) for many other values of n.

A256250 Total number of ON states after n generations of a cellular automaton on the square grid.

Original entry on oeis.org

1, 5, 9, 21, 25, 37, 57, 85, 89, 101, 121, 149, 185, 229, 281, 341, 345, 357, 377, 405, 441, 485, 537, 597, 665, 741, 825, 917, 1017, 1125, 1241, 1365, 1369, 1381, 1401, 1429, 1465, 1509, 1561, 1621, 1689, 1765, 1849, 1941, 2041, 2149, 2265, 2389, 2521, 2661, 2809, 2965, 3129, 3301, 3481, 3669, 3865, 4069, 4281, 4501, 4729, 4965, 5209, 5461
Offset: 1

Views

Author

Omar E. Pol, Mar 20 2015

Keywords

Comments

A256251 gives the number of cells turned ON at n-th stage.
Note that the number of cells turned ON at n-th stage in each one of its four quadrants is also A006257 (Josephus problem). For more information see A256249.
It appears that this is also a bisection of A256249.
First differs from A169707 at a(13), but both sequences share infinitely many terms. This one is simpler. Compare A169707.

Examples

			Also, written as an irregular triangle T(n,k), k >= 1, in which the row lengths are the terms of A011782 the sequence begins:
1;
5;
9,   21;
25,  37, 57, 85;
89, 101,121,149,185,229,281,341;
345,357,377,405,441,485,537,597,665,741,825,917,1017,1125,1241,1365;
...
Right border gives the positive terms of A002450.
It appears that this triangle at least shares with the triangles from the following sequences; A147562, A162795, A169707, A255366, the positive elements of the columns k, if k is a power of 2.
		

Crossrefs

Programs

Formula

a(n) = 1 + 4*A256249(n-1), n >= 1.

A162794 Number of toothpicks added to the toothpick structure A139250 at the n-th even round.

Original entry on oeis.org

0, 2, 4, 8, 8, 8, 12, 28, 16, 8, 12, 28, 20, 28, 40, 88, 32, 8, 12, 28, 20, 28, 40, 88, 36, 28, 40, 88, 56, 92, 140, 256, 64, 8, 12, 28, 20, 28, 40, 88, 36, 28, 40, 88, 56, 92, 140, 256, 68, 28, 40, 88, 56, 92, 140, 256, 88, 92, 140, 260, 172, 296, 488, 704, 128, 8, 12, 28, 20, 28
Offset: 0

Views

Author

Omar E. Pol, Jul 14 2009

Keywords

Comments

Note that these toothpicks are orthogonal to the initial toothpick in the sieve.
A bisection of A139251.

Crossrefs

Extensions

Extended by R. J. Mathar, Sep 27 2009

A255263 Differences between the total number of ON cells at stage n of two-dimensional cellular automaton defined by "Rule 750" using the von Neumann neighborhood and the total number of toothpicks in the toothpick structure A139250 that are parallel to the initial toothpick, after n odd rounds.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 4, 0, 4, 12, 20, 0, 0, 0, 4, 0, 4, 12, 20, 0, 4, 12, 20, 12, 36, 80, 68, 0, 0, 0, 4, 0, 4, 12, 20, 0, 4, 12, 20, 12, 36, 80, 68, 0, 4, 12, 20, 12, 36, 80, 68, 12, 36, 80, 84, 96, 208, 352, 196, 0, 0, 0, 4, 0, 4, 12, 20, 0, 4, 12, 20, 12, 36, 80, 68, 0, 4, 12, 20, 12, 36, 80, 68, 12, 36, 80
Offset: 1

Views

Author

Omar E. Pol, Feb 19 2015

Keywords

Comments

It appears that the graph of A162795 lies between the graphs of A147562 and A169707.
It appears that a(n) = 0 if and only if n is a member of A048645.

Examples

			Written as an irregular triangle T(j,k), k>=1, in which the row lengths are the terms of A011782:
0;
0;
0,0;
0,0,4,0;
0,0,4,0,4,12,20,0;
0,0,4,0,4,12,20,0,4,12,20,12,36,80,68,0;
0,0,4,0,4,12,20,0,4,12,20,12,36,80,68,0,4,12,20,12,36,80,68,12,36,80,84,96,208,352,196,0;
...
It appears that if k is a power of 2 then T(j,k) = 0.
		

Crossrefs

Formula

a(n) = A169707(n) - A162795(n).

A255264 Total number of ON cells in the "Ulam-Warburton" two-dimensional cellular automaton of A147562 after A048645(n) generations.

Original entry on oeis.org

1, 5, 9, 21, 25, 37, 85, 89, 101, 149, 341, 345, 357, 405, 597, 1365, 1369, 1381, 1429, 1621, 2389, 5461, 5465, 5477, 5525, 5717, 6485, 9557, 21845, 21849, 21861, 21909, 22101, 22869, 25941, 38229, 87381, 87385, 87397, 87445, 87637
Offset: 1

Views

Author

Omar E. Pol, Feb 19 2015

Keywords

Comments

It appears that these are the terms of A147562, A162795, A169707, A255366, A256250, A256260, whose indices have binary weight 1 or 2.

Examples

			Also, written as an irregular triangle in which row lengths are the terms of A028310 the sequence begins:
      1;
      5;
      9,    21;
     25,    37,    85;
     89,   101,   149,   341;
    345,   357,   405,   597,  1365;
   1369,  1381,  1429,  1621,  2389,  5461;
   5465,  5477,  5525,  5717,  6485,  9557, 21845;
  21849, 21861, 21909, 22101, 22869, 25941, 38229, 87381;
  ...
Right border gives the positive terms of A002450.
It appears that the second leading diagonal gives the odd terms of A206374.
		

Crossrefs

Formula

a(n) = A147562(A048645(n)).
Conjecture 1: a(n) = A162795(A048645(n)).
Conjecture 2: a(n) = A169707(A048645(n)).
Conjecture 3: a(n) = A255366(A048645(n)).
Conjecture 4: a(n) = A256250(A048645(n)).
Conjecture 5: a(n) = A256260(A048645(n)).
a(n) = A032925(A209492(n-1)) (conjectured). - Jon Maiga, Dec 17 2021

A255737 Total number of toothpicks in the toothpick structure of A153000 that are parallel to the initial toothpick, after n odd rounds.

Original entry on oeis.org

0, 1, 2, 5, 6, 9, 13, 21, 22, 25, 29, 37, 41, 50, 65, 85, 86, 89, 93, 101, 105, 114, 129, 149, 153, 162, 177, 198, 213, 241, 293, 341, 342, 345, 349, 357, 361, 370, 385, 405, 409, 418, 433, 454, 469, 497, 549, 597, 601, 610, 625, 646, 661, 689, 741, 790, 805, 833, 885, 941, 994, 1085, 1253, 1365, 1366, 1369
Offset: 0

Views

Author

Omar E. Pol, Mar 07 2015

Keywords

Comments

Total number of toothpicks in the first quadrant of the toothpick structure of A139250 that are parallel to the initial toothpick, after n odd rounds.
Written as an irregular triangle in which the row lengths are the terms of A011782 the right border gives A002450.

Crossrefs

Formula

a(n) = (A162795(n+1) - 1)/4.

A194800 Number of grid points that are covered after n-th stage of A139250, assuming the vertical toothpicks have length 2 and the horizontal toothpicks have length 4.

Original entry on oeis.org

0, 3, 11, 17, 31, 39, 67
Offset: 0

Views

Author

Omar E. Pol, Sep 07 2011

Keywords

Comments

There are an infinite family of these sequences since A139250 gives the number of toothpicks in the structure regardless of the length difference between horizontal toothpicks and vertical toothpicks. Examples: A147614, this sequence, A194802, A160420, etc.

Examples

			a(2) = 11.
o o o o o
. . o . .
o o o o o
		

Crossrefs

A194802 Number of grid points that are covered after n-th stage of A139250, assuming the vertical toothpicks have length 4 and the horizontal toothpicks have length 2.

Original entry on oeis.org

0, 5, 9, 23, 29, 45, 57
Offset: 0

Views

Author

Omar E. Pol, Sep 07 2011

Keywords

Comments

There are an infinite family of these sequences since A139250 gives the number of toothpicks in the structure regardless of the length difference between horizontal toothpicks and vertical toothpicks. Examples: A147614, A194800, this sequence, A160420, etc.

Examples

			a(2) = 9.
o o o
. o .
. o .
. o .
o o o
		

Crossrefs

Previous Showing 11-20 of 23 results. Next