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 1-7 of 7 results.

A173452 a(n) = A048883(n-1) - A151710(n).

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 6, -6, 6, 0, 30, 0, 0, 0, 6, -6, 6, 0, 30, -12, 6, 0, 30
Offset: 1

Views

Author

Omar E. Pol, May 29 2010

Keywords

Comments

It appears that the absolute value of a(n) is a multiple of 6, see A008588. - Omar E. Pol, Dec 06 2013

Examples

			From _Omar E. Pol_, Dec 06 2013: (Start)
Written as an irregular triangle in which row lengths is A011782 the sequence begins:
0;
0;
0, 0;
0, 0, 0, 6;
0, 0, 0, 6, -6, 6, 0, 30;
0, 0, 0, 6, -6, 6, 0, 30, -12, 6, 0, 30...
(End)
		

Crossrefs

A173453 a(n) = A160121(n) - A151710(n).

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 0, 24, 0, 0, 0, 0, 0, 0, 0, 12, 0, 0, 0, 0, 0, 0, 0, 78
Offset: 1

Views

Author

Omar E. Pol, May 29 2010

Keywords

Crossrefs

A173465 a(n) = A151710(n+1)/3.

Original entry on oeis.org

1, 1, 3, 1, 3, 3, 7, 1, 3, 3, 7, 5, 7, 9, 17, 1, 3, 3, 7, 5, 7, 9, 17, 7, 7, 9, 17, 17, 19, 23, 39, 1
Offset: 1

Views

Author

Omar E. Pol, May 29 2010

Keywords

Comments

First 23 terms the same as A151837.

Examples

			If written as a triangle, begins:
1;
1,3;
1,3,3,7;
1,3,3,7,5,7,9,17;
1,3,3,7,5,7,9,17,7,7,9,17,17,19,23,39;
		

Crossrefs

A160121 First differences of A160120.

Original entry on oeis.org

1, 3, 3, 9, 3, 9, 9, 21, 9, 9, 9, 21, 15, 21, 27, 51, 27, 9, 9, 21, 15, 21, 27, 51, 33, 21, 27, 51, 51, 57, 69, 117, 81, 21, 9, 21, 15, 21, 27, 51, 33, 21, 27, 51, 51, 57, 69, 117, 87, 33, 27, 51, 51, 57, 75, 129, 117, 75, 69, 117, 135, 141, 171, 279, 231, 69, 9, 21, 15, 21, 27
Offset: 1

Views

Author

Omar E. Pol, May 02 2009

Keywords

Comments

Number of Y-toothpicks added at n-th stage to the Y-toothpick structure of A160120.
For a simpler version, see A151710. - Omar E. Pol, Dec 18 2012

Examples

			Contribution from _Omar E. Pol_, Jun 18 2009: (Start)
May be written as a triangle:
1,
3,
3,
9,
3,9,
9,21,9,9,
9,21,15,21,27,51,27,9,
9,21,15,21,27,51,33,21,27,51,51,57,69,117,81,21,
9,21,15,21,27,51,33,21,27,51,51,57,69,117,87,33,27,51,51,57,75,129,117,75,69,117,135,141,171,279,231,69;
Rows converge to A161326.
(End)
Contribution from _Omar E. Pol_, Dec 18 2012: (Start):
Also this sequence may be written as another triangle (according to the structure of triangle A151710):
1;
3;
3,  9;
3,  9,9,21;
9,  9,9,21,15,21,27,51;
27, 9,9,21,15,21,27,51,33,21,27,51,51,57,69,117;
81,21,9,21,15,21,27,51,33,21,27,51,51,57,69,117,87,33,27,51,51,57,75,129,117,75,69,117,135,141,171,279;
(End)
		

Crossrefs

Programs

  • Mathematica
    YTPFunc[lis_, step_] := With[{out = Extract[lis, {{1, 2}, {2, 1}, {-1, -1}}], in = lis[[2, 2]]}, Which[in == 1, 3, in == 0 && Count[out, 1] >= 2, 2, in == 0 && Count[out, 1] == 1, 1, True, in]]; A160121[n_] := Count[CellularAutomaton[{YTPFunc, {}, {1, 1}}, {{{1}}, 0}, {{{n}}}], 1, 2] (* JungHwan Min, Jan 28 2016 *)
    A160121[n_] := Count[CellularAutomaton[{13390417258775213635414055181254541831894674613399006361662885886563211940509571858857491972104491013971547937418035084866785430974106432144737472376143620, 4, {{-1, 0}, {0, -1}, {0, 0}, {1, 1}}}, {{{1}}, 0}, {{{n}}}], 1, 2] (* JungHwan Min, Jan 28 2016 *)

Extensions

More terms from David Applegate, Jun 14 2009

A160715 Y-toothpick sequence (as A160120) but without internal propagation in the structure.

Original entry on oeis.org

0, 1, 4, 7, 16, 19, 28, 37, 58, 61, 70, 79, 100, 115, 136, 163, 214, 217, 226, 235, 256, 271, 292, 319, 370, 391, 412, 439, 490, 541, 598, 667, 784, 787
Offset: 0

Views

Author

Omar E. Pol, Jun 02 2009

Keywords

Comments

Note that A160120(9)=67 but in this sequence a(9)=61.
See the entry A160120 for more information about the Y-toothpick sequences.

Crossrefs

Extensions

More terms from Omar E. Pol, May 29 2010

A173451 a(n) = A048883(n-1) - A160121(n).

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 6, -6, 0, 0, 6, -6, 6, 0, 30, -24, 0, 0, 6, -6, 6, 0, 30, -24, 6, 0, 30, -24, 24, 12, 126, -78, -12, 0, 6, -6, 6, 0, 30, -24, 6, 0, 30, -24, 24, 12, 126, -78, -6, 0, 30, -24, 24, 6, 114, -90, 6, 12, 126, -54, 102, 72, 450, -228, -60, 0, 6, -6, 6, 0
Offset: 1

Views

Author

Omar E. Pol, May 29 2010

Keywords

Comments

It appears that the absolute value of a(n) is a multiple of 6, see A008588. - Omar E. Pol, Dec 06 2013

Examples

			From _Omar E. Pol_, Dec 06 2013: (Start)
Written as an irregular triangle in which row lengths is A011782 the sequence begins:
.    0;
.    0;
.    0,  0;
.    0,  0,0,6;
.   -6,  0,0,6,-6,6,0,30;
.  -24,  0,0,6,-6,6,0,30,-24,6,0,30,-24,24,12,126;
.  -78,-12,0,6,-6,6,0,30,-24,6,0,30,-24,24,12,126,-78,-6,0,30,-24,24,6,114,-90,6,12,126,-54,102,72,450;
. -228,-60,0,6,-6,6,0...
(End)
		

Crossrefs

Extensions

More terms from Nathaniel Johnston, Nov 15 2010

A266533 First differences of A266532.

Original entry on oeis.org

1, 3, 3, 9, 3, 9, 9, 21, 3, 9, 9, 21, 9, 21, 21, 45, 3, 9, 9, 21, 9, 21, 21, 45, 9, 21, 21, 45, 21, 45, 45, 93, 3, 9, 9, 21, 9, 21, 21, 45, 9, 21, 21, 45, 21, 45, 45, 93, 9, 21, 21, 45, 21, 45, 45, 93, 21, 45, 45, 93, 45, 93, 93, 189, 3, 9, 9, 21, 9, 21, 21, 45, 9, 21, 21, 45, 21, 45, 45, 93
Offset: 1

Views

Author

David Applegate and Omar E. Pol, Jan 18 2016

Keywords

Comments

Number of Y-toothpicks added at n-th stage in the structure of A266532.
A simplified version of A160121.

Examples

			Written as an irregular triangle in which the row lengths are the terms of A011782 the sequence begins:
1;
3;
3, 9;
3, 9, 9, 21;
3, 9, 9, 21, 9, 21, 21, 45;
3, 9, 9, 21, 9, 21, 21, 45, 9, 21, 21, 45, 21, 45, 45, 93;
...
Observation: at least the first 11 terms of the right border coincide with A068156.
		

Crossrefs

Formula

a(1) = 1. It appears that a(n) = 3*A038573(n-1), n >= 2.
Showing 1-7 of 7 results.