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.

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A211016 Triangle read by rows: T(n,k) = number of squares and rectangles of area 2^(k-1) after 2^n stages in the toothpick structure of A139250, n>=1, k>=1, assuming the toothpicks have length 2.

Original entry on oeis.org

0, 0, 4, 8, 12, 4, 40, 52, 12, 4, 168, 212, 52, 12, 4, 680, 852, 212, 52, 12, 4, 2728, 3412, 852, 212, 52, 12, 4, 10920, 13652, 3412, 852, 212, 52, 12, 4, 43688, 54612, 13652, 3412, 852, 212, 52, 12, 4, 174760, 218452, 54612, 13652, 3412, 852, 212, 52, 12, 4
Offset: 1

Views

Author

Omar E. Pol, Sep 18 2012

Keywords

Comments

All internal regions in the toothpick structure are squares and rectangles.

Examples

			For n = 5 in the toothpick structure after 2^5 stages we have that:
T(5,1) = 168 is the number of squares of size 1 X 1.
T(5,2) = 212 is the number of rectangles of size 1 X 2.
T(5,3) = 52 is the total number of squares of size 2 X 2 and of rectangles of size 1 X 4.
T(5,4) = 12 is the number of rectangles of size 2 X 4.
T(5,5) = 4 is the number of rectangles of size 2 X 8.
Triangle begins:
       0;
       0,      4;
       8,     12,     4;
      40,     52,    12,     4;
     168,    212,    52,    12,    4;
     680,    852,   212,    52,   12,   4;
    2728,   3412,   852,   212,   52,  12,   4;
   10920,  13652,  3412,   852,  212,  52,  12,  4;
   43688,  54612, 13652,  3412,  852, 212,  52, 12,  4;
  174760, 218452, 54612, 13652, 3412, 852, 212, 52, 12, 4;
		

Crossrefs

Row sums give 0 together with A145655.

Formula

T(n,k) = A211008(2^n,k) = 4*A211019(n,k).
T(n,1) = 4*A020988(n-2), n>=2.

A160128 a(n) = number of grid points that are covered after (2^n)th stage of A139250.

Original entry on oeis.org

3, 7, 19, 63, 235, 919, 3651, 14575, 58267, 233031, 932083, 3728287, 14913099, 59652343, 238609315, 954437199, 3817748731, 15270994855, 61083979347, 244335917311, 977343669163, 3909374676567, 15637498706179
Offset: 0

Views

Author

Omar E. Pol, May 09 2009

Keywords

Crossrefs

Programs

  • PARI
    Vec((3 - 11*x + 4*x^2) / ((1 - x)^2*(1 - 4*x)) + O(x^40)) \\ Colin Barker, May 13 2020

Formula

a(n) = A147614(A000079(n)).
a(n) = (1/9)*(2^(2*n+3) + 12*n + 19). [Nathaniel Johnston, Mar 29 2011]
It appears that a(n) = A139252(2^(n+1)). - Omar E. Pol, Sep 11 2012
a(n) = 6*a(n-1) - 9*a(n-2) + 4*a(n-3). - Paul Curtz, May 07 2020
G.f.: (3 - 11*x + 4*x^2) / ((1 - x)^2*(1 - 4*x)). - Colin Barker, May 13 2020

Extensions

Terms after a(10) from Nathaniel Johnston, Mar 29 2011

A211017 T(n,k) = total area of all squares and rectangles of area 2^(k-1) after 2^n stages in the toothpick structure of A139250, n>=1, k>=1, assuming the toothpicks have length 2. Triangle read by rows.

Original entry on oeis.org

0, 0, 8, 8, 24, 16, 40, 104, 48, 32, 168, 424, 208, 96, 64, 680, 1704, 848, 416, 192, 128, 2728, 6824, 3408, 1696, 832, 384, 256, 10920, 27304, 13648, 6816, 3392, 1664, 768, 512, 43688, 109924, 54608, 27296, 13632, 6784, 3328, 1536, 1024
Offset: 1

Views

Author

Omar E. Pol, Sep 21 2012

Keywords

Comments

All internal regions in the toothpick structure are squares and rectangles. The area of every internal region is a power of 2.

Examples

			For n = 5 in the toothpick structure after 2^5 stages we have that:
T(5,1) = 168 is the total area of all squares of size 1 X 1.
T(5,2) = 424 is the total area of all rectangles of size 1 X 2.
T(5,3) = 208 is the total area of all squares of size 2 X 2 and of all rectangles of size 1 X 4.
T(5,4) = 96 is the total area of all rectangles of size 2 X 4.
T(5,5) = 64 is the total area of all rectangles of size 2 X 8.
Triangle begins:
      0;
      0,     8;
      8,    24,    16;
     40,   104,    48,   32;
    168,   424,   208,   96,   64;
    680,  1704,   848,  416,  192,  128;
   2728,  6824,  3408, 1696,  832,  384, 256;
  10920, 27304, 13648, 6816, 3392, 1664, 768, 512;
		

Crossrefs

Formula

T(n,k) = A211016(n,k)*2^(k-1).
T(n,1) = 4*A020988(n-2), n>=2.

A211019 Triangle read by rows: T(n,k) = number of squares and rectangles of area 2^(k-1) after 2^n stages in the toothpick structure of A139250, divided by 4, n>=1, k>=1, assuming the toothpicks have length 2.

Original entry on oeis.org

0, 0, 1, 2, 3, 1, 10, 13, 3, 1, 42, 53, 13, 3, 1, 170, 213, 53, 13, 3, 1, 682, 853, 213, 53, 13, 3, 1, 2730, 3413, 853, 213, 53, 13, 3, 1, 10922, 13653, 3413, 853, 213, 53, 13, 3, 1, 43690, 54613, 13653, 3413, 853, 213, 53, 13, 3, 1, 174762, 218453
Offset: 1

Views

Author

Omar E. Pol, Sep 24 2012

Keywords

Comments

All internal regions in the toothpick structure are squares and rectangles.

Examples

			Triangle begins:
0;
0,         1;
2,         3,     1;
10,       13,     3,    1;
42,       53,    13,    3,   1;
170,     213,    53,   13,   3,   1;
682,     853,   213,   53,  13,   3,  1;
2730,   3413,   853,  213,  53,  13,  3,  1;
10922, 13653,  3413,  853, 213,  53, 13,  3, 1;
43690, 54613, 13653, 3413, 853, 213, 53, 13, 3, 1;
		

Crossrefs

Row sums give 0 together with A014825.

Formula

T(n,k) = A211016(n,k)/4.
T(n,1) = A020988(n-2), n>=2.

A151885 Similar to the original toothpick sequence A139250, except that the rule is now: a toothpick changes state if its midpoint is adjacent to exactly one ON toothpick.

Original entry on oeis.org

0, 1, 3, 5, 11, 5, 15, 17, 39, 5, 15, 25, 55, 17, 51, 61, 139, 5, 15, 25, 55, 25, 75, 85, 195, 17, 51, 85, 187, 61, 183, 217, 495, 5, 15, 25, 55, 25, 75, 85, 195, 25, 75, 125, 275, 85, 255, 305, 695, 17, 51, 85, 187, 85, 255, 289, 663
Offset: 0

Views

Author

N. J. A. Sloane, Jul 23 2009

Keywords

Comments

In the original toothpick sequence A139250, a toothpick simply turned ON (and stayed ON) if its midpoint was adjacent to exactly one ON toothpick.
Related to A139250 in the same way that A079315 is related to A147562.

Crossrefs

Formula

a(n) = a(n-1) + A151888(n).

Extensions

Terms after a(8) from Nathaniel Johnston, Apr 02 2011

A160126 Total number of squares and rectangles in the toothpick structure after n stages, divided by 2. (See A139250).

Original entry on oeis.org

0, 0, 0, 1, 2, 2, 4, 9, 12, 12, 14, 18, 20, 22, 32, 47, 54, 54, 56, 60, 62, 64, 74, 88, 94, 96, 104, 114, 120, 134, 170, 209, 224, 224, 226, 230, 232, 234, 244, 258, 264, 266, 274, 284, 290, 304, 340, 378, 392, 394, 402, 412, 418, 432, 466, 500, 514
Offset: 0

Views

Author

Omar E. Pol, May 03 2009

Keywords

Crossrefs

Formula

a(n) = A160124(n)/2. - Nathaniel Johnston, Apr 12 2011

Extensions

Terms beyond a(10) from Nathaniel Johnston, Apr 12 2011

A195853 Decimal expansion of the lower limit of A139250(i)/i^2.

Original entry on oeis.org

4, 5, 1, 3, 0, 5, 8, 2, 8, 4, 5, 3, 1, 2, 2, 1, 3, 5, 8, 9, 6, 4, 0, 1, 3, 4, 2, 2, 8, 0, 4, 0, 0, 1, 2, 3, 5, 1, 0, 2, 0, 4, 1, 3, 8, 3, 2, 9
Offset: 0

Views

Author

Omar E. Pol, Sep 27 2011

Keywords

Comments

Constant mentioned in the Applegate-Pol-Sloane article, Section 5, the fractal-like structure. It is also mentioned in A139250 and A170927.
Note that at least there are 162 constants starting with 0.451305 in the Plouffe's Inverter.
Also evidently half the lower limit of A147562(n)/n^2; see A260239. - Steven Finch, Jul 21 2015

Examples

			0.451305...
		

References

  • D. Applegate, Omar E. Pol and N. J. A. Sloane, The Toothpick Sequence and Other Sequences from Cellular Automata, Congressus Numerantium, Vol. 206 (2010), 157-191

Crossrefs

Extensions

a(6)-a(14) from Robert Price, Aug 18 2012
a(15)-a(47) from Robert Price, Aug 16 2015
Removed first fifteen terms as they were duplicated in the last edit by Robert Price, Dec 17 2018

A211018 Triangle read by rows: T(n,k) = total area of all squares and rectangles of area 2^(k-1) after 2^n stages in the toothpick structure of A139250, divided by 8, n>=1, k>=1, assuming the toothpicks have length 2.

Original entry on oeis.org

0, 0, 1, 1, 3, 2, 5, 13, 6, 4, 21, 53, 26, 12, 8, 85, 213, 106, 52, 24, 16, 341, 853, 426, 212, 104, 48, 32, 1365, 3413, 1706, 852, 424, 208, 96, 64, 5461, 13653, 6826, 3412, 1704, 848, 416, 192, 128, 21845, 54613, 27306, 13652, 6824, 3408, 1696, 832, 384, 256
Offset: 1

Views

Author

Omar E. Pol, Sep 24 2012

Keywords

Comments

All internal regions in the toothpick structure are squares and rectangles. The area of every internal region is a power of 2.

Examples

			0;
0,        1;
1,        3,    2;
5,       13,    6,    4;
21,      53,   26,   12,    8;
85,     213,  106,   52,   24,  16;
341,    853,  426,  212,  104,  48,  32;
1365,  3413, 1706,  852,  424, 208,  96,  64;
5461, 13653, 6826, 3412, 1704, 848, 416, 192, 128;
		

Crossrefs

Rows sums give A006516. Right border gives A131577.

Formula

T(n,k) = A211017(n,k)/8.
T(n,1) = A002450(n-2), n>=2.

A159790 Toothpick number A139250(n) minus triangular number A000217(n).

Original entry on oeis.org

0, 0, 0, 1, 1, 0, 2, 7, 7, 2, 0, 1, 1, 4, 18, 35, 35, 22, 12, 5, -3, -8, -2, 7, 3, -6, -4, 5, 17, 48, 106, 155, 155, 126, 100, 77, 53, 32, 22, 15, -5, -30, -44, -51, -55, -40, 2, 35, 23, -10, -32, -47, -59, -52, -18, 11, 11, 14, 48, 101, 181, 328, 522, 651, 651, 590, 532
Offset: 0

Views

Author

Omar E. Pol, May 03 2009

Keywords

Extensions

More terms from R. J. Mathar, May 04 2009

A160570 Triangle read by rows, A160552 convolved with (1, 2, 2, 2, ...); row sums = A139250, the Toothpick sequence.

Original entry on oeis.org

1, 1, 2, 3, 2, 2, 1, 6, 2, 2, 3, 2, 6, 2, 2, 5, 6, 2, 6, 2, 2, 7, 10, 6, 2, 6, 2, 2, 1, 14, 10, 6, 2, 6, 2, 2, 3, 2, 14, 10, 6, 2, 6, 2, 2, 5, 6, 2, 14, 10, 6, 2, 6, 2, 2, 7, 10, 6, 2, 14, 10, 6, 2, 6, 2, 2, 5, 14, 10, 6, 2, 14, 10, 6, 2, 6, 2, 2, 11, 10, 14, 10, 6, 2, 14, 10, 6, 2, 6
Offset: 1

Views

Author

Gary W. Adamson, May 19 2009

Keywords

Examples

			First few rows of the triangle:
  1;
  1,  2;
  3,  2,  2;
  1,  6,  2,  2;
  3,  2,  6,  2,  2;
  5,  6,  2,  6,  2,  2;
  7, 10,  6,  2,  6,  2,  2;
  1, 14, 10,  6,  2,  6,  2,  2;
  3,  2, 14, 10,  6,  2,  6,  2,  2;
  5,  6,  2, 14, 10,  6,  2,  6,  2,  2;
  ...
Example: Row 4 = (1, 6, 2, 2) = (1, 3, 1, 1) dot (1, 2, 2, 2); where (1 + 6 + 2 + 2) = A139250(4), i.e., 4th term in the Toothpick sequence.
		

Crossrefs

Programs

  • Maple
    T:=proc(n,k)if(k=1)then return A160552(n):else return 2*A160552(n-k+1):fi:end:
    for n from 1 to 8 do for k from 1 to n do print(T(n,k));od:od: # Nathaniel Johnston, Apr 13 2011

Formula

Construct triangle M = an infinite lower triangular Toeplitz matrix with A160552: (1, 1, 3, 1, 3, 5, 7, ...) in every column. Let Q = an infinite lower triangular matrix with (1, 2, 2, 2, 2, ...) as the main diagonal and the rest zeros. A160570 = M * Q.
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