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 11-17 of 17 results.

A222180 Total number of ON states after n generations of cellular automaton based on pentagons. Also P-toothpick sequence (see Comments lines for definition).

Original entry on oeis.org

0, 1, 6, 16, 26, 36, 56, 86, 106, 116, 136, 176, 216, 246, 296, 366, 406, 416, 436, 476, 536, 616
Offset: 0

Views

Author

Omar E. Pol, Mar 15 2013

Keywords

Comments

Analog of A161644, A147562 and A151723, but here we are working without a lattice. Each regular pentagon has five virtual neighbors. Overlapping are prohibited. The sequence gives the number of pentagons in the structure after n-th stage. A222181 (the first differences) gives the number of pentagons added at n-th stage.
Also this is a P-toothpick sequence since every pentagon can be replaced by a P-toothpick which is formed by five toothpicks as a five-pointed star. Note that each toothpick can be represented as an apothem or as a radius of a pentagon. In both types of structures the number of toothpicks after n-th stage is equal to 5*a(n).

Crossrefs

Formula

a(n) = 6 + 10*A222172(n-2), n >= 2. - Omar E. Pol, Nov 24 2013

Extensions

Name improved by Omar E. Pol, Nov 24 2013

A222181 Number of pentagons added at n-th stage to the structure of A222180.

Original entry on oeis.org

0, 1, 5, 10, 10, 10, 20, 30, 20, 10, 20, 40, 40, 30, 50, 70, 40, 10, 20, 40, 60, 80
Offset: 0

Views

Author

Omar E. Pol, Mar 15 2013

Keywords

Comments

Essentially the first differences of A222180.
Also number of P-toothpicks added at n-th stage to the P-toothpick structure of A222180.

Examples

			Apparently this is an irregular triangle:
0;
1;
5;
10,10;
10,20,30,20;
10,20,40,40,30,50,70,40;
10,20,40,60,80,...
		

Crossrefs

Formula

a(n) = 10*A222173(n-2), n >= 3. - Omar E. Pol, Nov 24 2013

A222177 Number of pentagons added at n-th stage to the structure of A222176.

Original entry on oeis.org

0, 1, 2, 2, 2, 4, 6, 4, 2, 4, 8, 8, 6, 10, 14, 8, 2, 4, 8, 12, 16
Offset: 0

Views

Author

Omar E. Pol, Mar 21 2013

Keywords

Comments

Essentially the first differences of A222176.
Also number of P-toothpicks added at n-th stage to the P-toothpick structure of A222176.
First differs from A152968 at a(10).

Examples

			Apparently this is an irregular triangle:
0;
1;
2, 2;
2, 4, 6, 4;
2, 4, 8, 8, 6, 10, 14, 8;
2, 4, 8, 12, 16,...
		

Crossrefs

Formula

a(n) = A222181(n+1)/5, n >= 1.

A152979 Records in A152978.

Original entry on oeis.org

1, 2, 3, 4, 7, 8, 9, 10, 15, 22, 23, 28, 35, 52, 64, 65, 74, 91, 122, 168, 176, 177, 186, 239, 304, 412, 512, 513, 524, 527, 599, 782, 1020, 1336, 1488, 1489, 1500, 1575, 1980, 2584, 3376, 4160, 4161, 4172, 4174, 4247, 4275, 4653, 5010, 6544, 8544
Offset: 1

Views

Author

Omar E. Pol, Dec 23 2008

Keywords

Comments

This sequence also gives the records in A152980. - Nathaniel Johnston, Apr 10 2011

Crossrefs

Extensions

a(16)-a(51) from Nathaniel Johnston, Apr 10 2011

A152999 Primes in toothpick sequence A152998.

Original entry on oeis.org

3, 5, 7, 11, 17, 23, 47, 61, 97, 103, 151, 173, 191, 211, 241, 347, 353, 359, 367, 397, 467, 541, 599, 607, 659, 733, 1109, 1237, 1367, 1439, 1453, 1471, 1663, 2029, 2357, 2399, 2671, 2797, 3373, 3607, 3719, 3911, 4241, 5479, 5501, 5527, 5701, 5741, 5779, 5923
Offset: 1

Views

Author

Omar E. Pol, Dec 23 2008

Keywords

Crossrefs

Extensions

More terms from Jinyuan Wang, Mar 15 2020

A159785 a(n) = A152980(n)*3.

Original entry on oeis.org

3, 6, 9, 9, 12, 21, 24, 15, 12, 21, 27, 30, 45, 66, 60, 27, 12, 21, 27, 30, 45, 66, 63, 42, 45, 69, 84, 105, 156, 192, 144, 51, 12, 21, 27, 30, 45, 66, 63, 42, 45, 69, 84, 105, 156, 192, 147, 66, 45, 69, 84, 105, 156, 195, 168, 129, 159, 222, 273, 366, 504, 528
Offset: 1

Views

Author

Omar E. Pol, May 02 2009

Keywords

Crossrefs

Toothpick sequence: A139250.

Extensions

More terms from 3*A152980(n) by Jinyuan Wang, Mar 14 2020

A162627 a(n) = A162625(n+1)/2.

Original entry on oeis.org

2, 3, 3, 4, 6, 7, 5, 4, 6, 8, 10, 14, 18, 17, 9, 4, 6, 8, 10, 14, 18, 18, 14, 14, 20, 26, 34, 46, 52, 41, 17, 4, 6, 8, 10, 14, 18, 18, 14, 14, 20, 26, 34, 46, 52, 42, 22, 14, 20, 26, 34, 46, 54, 50, 42, 48, 66, 86, 114, 144, 144, 97, 33, 4, 6, 8, 10, 14, 18, 18
Offset: 1

Views

Author

Omar E. Pol, Aug 05 2009

Keywords

Crossrefs

Extensions

More terms from Jinyuan Wang, Mar 03 2020
Previous Showing 11-17 of 17 results.