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 1-3 of 3 results.

A187211 First differences of A187210.

Original entry on oeis.org

0, 1, 4, 7, 12, 22, 20, 22, 40, 54, 40, 22, 40, 54, 56, 70, 120, 134, 72, 22, 40, 54, 56, 70, 120, 134, 88, 70, 120, 150, 168, 246, 360, 326, 136, 22, 40, 54, 56, 70, 120, 134, 88, 70, 120, 150, 168, 246, 360, 326, 152, 70, 120, 150, 168, 246, 360, 342, 232, 246, 376, 454, 568, 838, 1032
Offset: 0

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Author

Omar E. Pol, Mar 07 2011

Keywords

Comments

Number of Q-toothpicks added at n-th stage to the Q-toothpick structure of A187210.
For the connection with A139251, the first differences of the toothpick sequence A139250, see the Formula section. - Omar E. Pol, Apr 02 2016

Examples

			Written as an irregular triangle the sequence begins:
0;
1;
4;
7;
12;
22, 20;
22, 40, 54, 40;
22, 40, 54, 56, 70, 120, 134, 72;
22, 40, 54, 56, 70, 120, 134, 88, 70, 120, 150, 168, 246, 360, 326, 136;
...
The rows of this triangle tend to A188156.
From _Omar E. Pol_, Apr 02 2016: (Start)
For n = 5 we have that A139251(5-2) = 4, A267699(5-2) = 7 and A267695(5-1) = 7, so a(5) = 2*4 + 7 + 7 = 22.
For n = 10 we have that A139251(10-2) = 8, A267699(10-2) = 20 and A267695(10-1) = 4, so a(10) = 2*8 + 20 + 4 = 40.
(End)
Starting from a(3) = 7 the row lengths of triangle are the terms of A011782. - _Omar E. Pol_, Apr 04 2016
		

Crossrefs

Formula

a(2^n + 2) = 16 + 8(2^(n-1) - 1), n >= 3. [Nathaniel Johnston, Mar 26 2011]
From Omar E. Pol, Apr 02 2016: (Start)
a(n) = floor(sqrt(2*n^3)), if 0<=n<=2 or n=6.
a(n) = 2*A139251(n-2) + A267699(n-2) + A267695(n-1), if 3<=n<=5 or n>=7.
(End)

Extensions

Terms after a(7) from Nathaniel Johnston, Mar 26 2011

A267698 Q-toothpick sequence in the first quadrant starting with two Q-toothpicks centered at (1,3) and (3,1) respectively. The endpoints of the left hand Q-toothpick are at (0,3) and (1,4). The endpoints of the right hand Q-toothpick are at (3,0) and (4,1). With a(0) = 0.

Original entry on oeis.org

0, 2, 6, 13, 25, 32, 44, 59, 79, 86, 98, 113, 133, 148, 176, 215, 251, 258, 270, 285, 305, 320, 348, 387, 423, 438
Offset: 0

Views

Author

Omar E. Pol, Jan 23 2016

Keywords

Comments

a(n) is the total number of Q-toothpicks in the structure after n-th stage.
A267699 (the first differences) gives the number of Q-toothpicks added at n-th stage.
Note that this sequence is also related with the structure and the formula of A187210. For more information see A187210, A267694 and A139250.

Crossrefs

A267695 First differences of A267694.

Original entry on oeis.org

0, 2, 3, 4, 7, 4, 7, 12, 15, 4, 7, 12, 15, 12, 23, 36, 31, 4, 7, 12, 15, 12, 23, 36, 31, 12
Offset: 0

Views

Author

Omar E. Pol, Apr 02 2016

Keywords

Comments

Number of Q-toothpicks added at n-th stage to the Q-toothpick structure of A267694.

Examples

			When the positive terms are written as an irregular triangle in which the row lengths are the terms of A011782 the sequence begins:
2;
3;
4, 7;
4, 7, 12, 15;
4, 7, 12, 15, 12, 23, 36, 31;
4, 7, 12, 15, 12, 23, 36, 31, 12,...
		

Crossrefs

Showing 1-3 of 3 results.