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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A151922 Number of first-quadrant cells (including the two boundaries) that are "ON" after n-th stage of the Holladay-Ulam cellular automaton.

Original entry on oeis.org

1, 3, 5, 9, 11, 15, 19, 29, 31, 35, 39, 49, 53, 63, 73, 101, 103, 107, 111, 121, 125, 135, 145, 173, 177, 187, 197, 225, 235, 263, 291, 373, 375, 379, 383, 393, 397, 407, 417, 445, 449, 459, 469, 497, 507, 535, 563, 645
Offset: 0

Views

Author

N. J. A. Sloane, Aug 05 2009

Keywords

Comments

See A079314, the first differences and A147562, the main entry for this CA, for further information.

Crossrefs

Programs

  • Mathematica
    A151922list[nmax_]:=Accumulate[Join[{1},3^(DigitCount[Range[nmax],2,1]-1)+1]];A151922list[100] (* Paolo Xausa, Jun 29 2023 *)

Formula

a(n) = A079316(2n).

Extensions

Extended (a(30)-a(47)) and edited by Omar E. Pol, Nov 21 2010

A160158 Toothpick sequence starting from a segment of length 4 formed by two toothpicks.

Original entry on oeis.org

0, 2, 4, 8, 16, 24, 28, 36, 48, 56, 64, 80, 104, 124, 136, 156, 176, 184, 192, 208, 232, 252, 268, 296, 328, 352, 384, 440, 508, 560, 600, 652, 688, 696, 704, 720, 744, 764, 780, 808, 840, 864, 896, 952, 1020, 1072, 1116, 1176, 1224, 1248, 1280, 1336, 1404
Offset: 0

Views

Author

Omar E. Pol, May 29 2009

Keywords

Comments

The sequence gives the number of toothpicks in the sieve after n-th stage.

Crossrefs

Extensions

Extended beyond a(13) by R. J. Mathar, Jun 01 2009

A160409 First differences of toothpick numbers A160408.

Original entry on oeis.org

1, 1, 2, 4, 4, 4, 4, 4, 8, 16, 16, 8, 4, 4, 8
Offset: 1

Views

Author

Omar E. Pol, May 23 2009

Keywords

Comments

Number of toothpick added to the toothpick pyramid at the round n.
See also the toothpick sequences A139250, A160160 and the toothpick triangle A160406.

Examples

			Contribution from _Omar E. Pol_, Jun 06 2009: (Start)
Array begins:
========
x, y, z
========
1, 1, 2;
4, 4, 4;
4, 4, 8;
16, 16, 8;
4, 4, 8;
(End)
		

Crossrefs

Extensions

More terms from Omar E. Pol, Jun 06 2009

A160162 a(n) = A160158(n)/2.

Original entry on oeis.org

0, 1, 2, 4, 8, 12, 14, 18, 24, 28, 32, 40, 52, 62, 68, 78, 88, 92, 96, 104, 116, 126, 134, 148, 164, 176, 192, 220, 254, 280, 300, 326, 344, 348, 352, 360, 372, 382, 390, 404, 420, 432, 448, 476, 510, 536, 558, 588, 612, 624, 640, 668, 702, 730, 760, 804, 848
Offset: 0

Views

Author

Omar E. Pol, May 29 2009

Keywords

Crossrefs

Extensions

Extended beyond a(13) by R. J. Mathar, Jun 01 2009

A161412 V-toothpick sequence starting at the corner of an infinite square from which protrudes a half toothpick with an angle = Pi/6.

Original entry on oeis.org

0, 1, 2, 3, 5, 9, 12, 15, 19, 25, 29, 34, 39, 49, 58, 63
Offset: 0

Views

Author

Omar E. Pol, Jun 10 2009

Keywords

Comments

The sequence gives the number of V-toothpicks in the structure after n rounds. A161413 (the first differences) gives the number added at the n-th round.

Crossrefs

V-toothpick sequence: A161206.

A161420 V-toothpick sequence starting from a V-toothpick whose central point touch a straight line, as a V.

Original entry on oeis.org

0, 1, 3, 5, 7, 11, 19, 25, 31, 39, 51, 59, 69, 79, 99, 117, 127, 143, 163, 171
Offset: 0

Views

Author

Omar E. Pol, Jun 10 2009

Keywords

Comments

The sequence gives the number of V-toothpicks after n-th stages on hexagonal net. A161421 (the first differences) gives the number added at the n-th stage. See A161206 for more information.
Also, it appears this is a H-toothpick sequence in the first quadrant on the square grid, starting with a D-toothpick from the point (0,0). The sequence gives the number of toothpicks and D-toothpicks after n-th stage. A161421 (the first differences) gives the number added at the n-th stage. For more information see A182838.

Crossrefs

A161832 a(n) = (A161830(n+1)-1)/2.

Original entry on oeis.org

0, 1, 2, 4, 5, 7, 9, 13, 15, 17, 19, 23, 26, 30, 35, 44, 49, 51
Offset: 0

Views

Author

Omar E. Pol, Jun 20 2009

Keywords

Comments

The sequence gives the number of Y-toothpicks in the structure after n rounds. A161833 (the first differences) gives the number added at the n-th round.
See the Y-toothpick sequence A160120 and A161830 for more information.

Crossrefs

A168112 Toothpick sequence starting with a straight line, with angle = Pi/4, from which protrudes a half toothpick.

Original entry on oeis.org

0, 1, 2, 4, 7, 10, 13, 19, 26, 32, 35, 41, 48, 56, 65, 81, 98, 108, 111, 117, 124, 132, 141, 157, 174, 186, 195, 211, 230, 252, 283, 329, 370, 388, 391, 397, 404, 412, 421, 437, 454, 466, 475, 491, 510, 532, 563, 609, 650, 670
Offset: 0

Views

Author

Omar E. Pol, Dec 07 2009

Keywords

Comments

On the infinite square grid, we start at round 0 drawing a straight line, with angle = Pi/4, from which protrudes a half toothpick.
At round 1 we place an orthogonal toothpick centered at the end.
In each subsequent round, for every exposed toothpick end, place an orthogonal toothpick centered at that end.
The sequence gives the number of toothpicks after n rounds.
See also A168113, the first differences.
For more information see A139250, which is the main entry for this sequence.

Crossrefs

Formula

a(n) = A160730(n)/2. [From Nathaniel Johnston, Mar 28 2011]

Extensions

Terms after a(34) from Nathaniel Johnston, Mar 28 2011

A160418 a(n) = A160407(n+2)/2.

Original entry on oeis.org

1, 1, 1, 1, 2, 2, 1, 1, 2, 2, 2, 3, 5, 4, 1, 1, 2, 2, 2, 3, 5, 4, 2, 3, 5, 5, 6, 10, 13, 8, 1, 1, 2, 2, 2, 3, 5, 4, 2, 3, 5, 5, 6, 10, 13, 8, 2, 3, 5, 5, 6, 10, 13, 9, 6, 10, 14, 15, 21, 32, 33, 16, 1, 1, 2, 2, 2, 3, 5, 4, 2, 3, 5, 5, 6, 10, 13, 8, 2, 3, 5, 5
Offset: 1

Views

Author

Omar E. Pol, May 23 2009

Keywords

Comments

Row lengths are the terms of A000079 multiplied by 2. Right border gives A000079. - Omar E. Pol, Mar 19 2020

Examples

			From _Omar E. Pol_, Mar 19 2020: (Start)
Triangle begins:
  1,1;
  1,1,2,2;
  1,1,2,2,2,3,5,4;
  1,1,2,2,2,3,5,4,2,3,5,5,6,10,13,8;
  1,1,2,2,2,3,5,4,2,3,5,5,6,10,13,8,2,3,5,5,6,10,13,9,6,10,14,15,21,32,33,16;
  ... (End)
		

Crossrefs

Extensions

More terms from Jinyuan Wang, Mar 14 2020

A160728 Toothpick cube: a(n) = A160408(n)*6.

Original entry on oeis.org

0, 6, 12, 24, 48, 72, 96, 120, 144, 192, 288, 384, 432, 456, 480, 528
Offset: 0

Views

Author

Omar E. Pol, Jun 06 2009

Keywords

Comments

Also, 6 times the toothpick pyramid A160408.
The sequence gives the number of toothpicks after n rounds. A160729 (the first differences) gives the number added at the n-th round.
See also the entry A139250 for more information about the toothpick sequences.

Crossrefs

Toothpick triangle: A160406. Toothpick pyramid: A160408.
Previous Showing 21-30 of 32 results. Next