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.

Showing 1-10 of 10 results.

A161829 First differences of A161828.

Original entry on oeis.org

0, 3, 0, 6, 0, 6, 6, 12, 6
Offset: 1

Views

Author

Omar E. Pol, Jun 21 2009

Keywords

Links

Crossrefs

Cf. A160120, A161419, A161828, A161837.

A161834 a(n) = A161828(n)/3.

Original entry on oeis.org

0, 0, 1, 1, 3, 3, 5, 7, 11, 13
Offset: 0

Views

Author

Omar E. Pol, Jun 21 2009

Keywords

Links

Crossrefs

Cf. A160120, A161422, A161828, A161838.

A162776 a(n) = A161828(n)*2/3.

Original entry on oeis.org

0, 0, 2, 2, 6, 6, 10, 14, 22, 26
Offset: 0

Views

Author

Omar E. Pol, Jul 17 2009

Keywords

Crossrefs

Cf. A160120, A161828, A161829, A161834.

A161418 Number of triangles in the Y-toothpick structure after n rounds.

Original entry on oeis.org

0, 0, 0, 0, 6, 6, 12, 12, 24, 30
Offset: 0

Views

Author

Omar E. Pol, Jun 21 2009

Keywords

Links

Crossrefs

Cf. A139250, A160120, A160124, A161419, A161828, A161836.

A161836 Number of concave-convex hexagons in the Y-toothpick structure of A160120 after n rounds.

Original entry on oeis.org

0, 0, 0, 0, 3, 3, 3, 3, 9, 15
Offset: 0

Views

Author

Omar E. Pol, Jun 21 2009

Keywords

Links

Crossrefs

Cf. A139250, A160120, A160124, A161419, A161418, A161828, A161837.

A194278 Total number of polygons after n-th stage in the D-toothpick structure of A194270.

Original entry on oeis.org

0, 0, 0, 0, 2, 8, 14, 16, 26, 38, 46, 48, 56, 72, 102
Offset: 0

Views

Author

Omar E. Pol, Aug 26 2011

Keywords

Comments

The structure of the D-toothpick cellular automaton contains at least several tens of different types of polygons. For more information see A194276 and A194277.

Examples

			Consider the structure with toothpicks of length 2 and D-toothpicks of length sqrt(2). After 3 stages the number of polygons in the structure is equal to 0. After 4 stages there are 2 hexagons, each with area = 6, so a(4) = 2. After 5 stages there are new 6 polygons: 2 hexagons, each with area = 8 and also 2 octagons, each with area = 14, so a(5) = 2+6 = 8.

Links

Crossrefs

Cf. A160124, A170926, A161418, A161828, A161836, A194270, A194276, A194277.

A161827 Complement of A006446.

Original entry on oeis.org

5, 7, 10, 11, 13, 14, 17, 18, 19, 21, 22, 23, 26, 27, 28, 29, 31, 32, 33, 34, 37, 38, 39, 40, 41, 43, 44, 45, 46, 47, 50, 51, 52, 53, 54, 55, 57, 58, 59, 60, 61, 62, 65, 66, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 78, 79, 82, 83, 84, 85, 86, 87, 88, 89, 91, 92, 93, 94, 95, 96, 97, 98
Offset: 1

Views

Author

Omar E. Pol, Jun 21 2009, Jun 28 2009, Feb 08 2010

Keywords

Comments

The asymptotic density of this sequence is 1 (Cooper and Kennedy, 1989). - Amiram Eldar, Jul 10 2020

Links

Crossrefs

Cf. A000005, A018253, A161205, A161344, A161345, A161424, A006446, A161828, A161835.

Extensions

More terms from N. J. A. Sloane, Feb 08 2010

A162190 Triangle read by rows in which row n lists the divisors of n, the n-th prime and the consecutive composites that are greater than the n-th prime, with a(0)=1.

Original entry on oeis.org

1, 1, 2, 1, 2, 3, 4, 1, 3, 5, 6, 1, 2, 4, 7, 8, 9, 10, 1, 5, 11, 12, 1, 2, 3, 6, 13, 14, 15, 16, 1, 7, 17, 18, 1, 2, 4, 8, 19, 20, 21, 22, 1, 3, 9, 23, 24, 25, 26, 27, 28, 1, 2, 5, 10, 29, 30, 1, 11, 31, 32, 33, 34, 35, 36, 1, 2, 3, 4, 6, 12, 37, 38, 39, 40
Offset: 0

Views

Author

Omar E. Pol, Jun 30 2009

Keywords

Examples

			Triangle begins:
1;
1,(2);
1,.2,(3),4;
1,....3,...(5),6;
1,.2,....4,......(7),8,.9,10;
1,..........5,..............(11),12;
1,.2,.3,.......6,..................(13),14,15,16;
1,................7,............................(17),18;
1,.2,....4,..........8,................................(19),20,21,22;

Links

Crossrefs

Cf. A000005, A000040, A000720, A027750, A018253, A160811, A160812, A161205, A161344, A161345, A161424, A006446, A161827, A161828, A161835.

A161416 Partial sums of A056737.

Original entry on oeis.org

0, 1, 3, 3, 7, 8, 14, 16, 16, 19, 29, 30, 42, 47, 49, 49, 65, 68, 86, 87, 91, 100, 122, 124, 124, 135, 141, 144, 172, 173, 203, 207, 215, 230, 232, 232, 268, 285, 295, 298, 338, 339, 381, 388, 392, 413, 459, 461, 461, 466, 480, 489, 541, 544, 550, 551, 567, 594
Offset: 1

Views

Author

Omar E. Pol, Jun 21 2009

Keywords

Links

Crossrefs

Cf. A056737, A018253, A160811, A160812, A161205, A161344, A161345, A161424, A006446, A161828, A161835, A219729, A219730.

Formula

a(n) = A219730(n) - A219729(n). - Tamas Sandor Nagy, Jan 20 2024

Extensions

Extended beyond a(16) by R. J. Mathar, Aug 01 2009

A162192 Triangle read by rows in which row n lists the divisors of n, prime(n), the consecutive composites that are greater than prime(n), and prime (n+1), but row 0 is formed by 1 and 2.

Original entry on oeis.org

1, 2, 1, 2, 3, 1, 2, 3, 4, 5, 1, 3, 5, 6, 7, 1, 2, 4, 7, 8, 9, 10, 11, 1, 5, 11, 12, 13, 1, 2, 3, 6, 13, 14, 15, 16, 17, 1, 7, 17, 18, 19, 1, 2, 4, 8, 19, 20, 21, 22, 23, 1, 3, 9, 23, 24, 25, 26, 27, 28, 29, 1, 2, 5, 10, 29, 30, 31
Offset: 0

Views

Author

Omar E. Pol, Jun 30 2009

Keywords

Comments

See also A162190, a sequence with a similar structure.

Examples

			Triangle begins:
1,(2);
1,(2),(3);
1,.2.,(3),4,(5);
1,.....3,...(5),6,(7);
1,.2,.....4,......(7),8,.9,10,(11);
1,...........5,...............(11),12,(13);
1,.2,..3,.......6,....................(13),14,15,16,(17);
1,.................7,...............................(17),18,(19);
1,.2,.....4,..........8,....................................(19),20,21,22,(23);

Links

Crossrefs

Cf. A000005, A000040, A000720, A027750, A018253, A160811, A160812, A161205, A161344, A161345, A161424, A006446, A161827, A161828, A161835, A162190.
Showing 1-10 of 10 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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