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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A151784 a(n) = 6^(wt(n) - 1) where wt(n) = A000120(n).

Original entry on oeis.org

1, 1, 6, 1, 6, 6, 36, 1, 6, 6, 36, 6, 36, 36, 216, 1, 6, 6, 36, 6, 36, 36, 216, 6, 36, 36, 216, 36, 216, 216, 1296, 1, 6, 6, 36, 6, 36, 36, 216, 6, 36, 36, 216, 36, 216, 216, 1296, 6, 36, 36, 216, 36, 216, 216, 1296, 36, 216, 216, 1296, 216, 1296, 1296, 7776, 1, 6, 6, 36, 6, 36, 36
Offset: 1

Views

Author

N. J. A. Sloane, Jun 25 2009

Keywords

Examples

			From _Omar E. Pol_, Jul 21 2009: (Start)
If written as a triangle:
  1;
  1,6;
  1,6,6,36;
  1,6,6,36,6,36,36,216;
  1,6,6,36,6,36,36,216,6,36,36,216,36,216,216,1296;
  1,6,6,36,6,36,36,216,6,36,36,216,36,216,216,1296,6,36,36,216,36,216,216,...
(End)
		

Crossrefs

Programs

  • PARI
    a(n) = 6^(hammingweight(n)-1); \\ Michel Marcus, Nov 15 2022

A183061 First differences of A183060.

Original entry on oeis.org

0, 1, 3, 3, 7, 3, 7, 7, 19, 3, 7, 7, 19, 7, 19, 19, 55, 3, 7, 7, 19, 7, 19, 19, 55, 7, 19, 19, 55, 19, 55, 55, 163, 3, 7, 7, 19, 7, 19, 19, 55, 7, 19, 19, 55, 19, 55, 55, 163, 7, 19, 19, 55, 19, 55, 55, 163, 19, 55, 55, 163, 55, 163, 163, 487, 3
Offset: 0

Views

Author

Omar E. Pol, Feb 20 2011

Keywords

Comments

The sequence gives the number of cells turned "ON" at the n-th stage in the structure of A183060.

Examples

			If written as a triangle begins:
0,
1,
3,
3,7,
3,7,7,19,
3,7,7,19,7,19,19,55,
3,7,7,19,7,19,19,55,7,19,19,55,19,55,55,163,
It appears that row sums give A007582.
It appears that last terms of rows give A100702.
		

Crossrefs

Formula

a(n) = 1 + A147582(n)/2.
a(n) = 1 + 2*A147610(n).

A183149 Number of toothpicks added at n-th stage to the toothpick structure of A183148.

Original entry on oeis.org

0, 1, 3, 9, 9, 21, 9, 21, 21, 57, 9, 21, 21, 57, 21, 57, 57, 165, 9, 21, 21, 57, 21, 57, 57, 165, 21, 57, 57, 165, 57, 165, 165, 489, 9, 21, 21, 57, 21, 57, 57, 165, 21, 57, 57, 165, 57, 165, 165, 489, 21, 57, 57, 165, 57, 165
Offset: 0

Views

Author

Omar E. Pol, Mar 28 2011, Apr 02 2011

Keywords

Comments

Essentially the first differences of A183148.

Examples

			If written as a triangle begins:
0,
1,
3,
9,
9,21,
9,21,21,57,
9,21,21,57,21,57,57,165,
9,21,21,57,21,57,57,165,21,57,57,165,57,165,165,489,
		

Crossrefs

Formula

a(n) = 3*A183061(n-1), for n >=2

A322663 First differences of A322662 divided by 12.

Original entry on oeis.org

1, 1, 7, 1, 6, 11, 14, 3, 11, 14, 25, 5, 18, 21, 37, 4, 11, 21, 50, 17, 31, 50, 50, 13, 32, 39, 70, 10, 42, 41, 81, 4, 11, 21, 50, 24, 57, 74, 89, 40, 62, 84, 105, 48, 66, 85, 111, 18, 37, 64, 151, 41, 80, 126, 131, 29
Offset: 1

Views

Author

Bradley Klee, Dec 22 2018

Keywords

Comments

Unlike A322050, this sequence contains only finitely many 1's. However, the Cellular Automaton and its counting sequences still admit a 2^n fractal structure (Cf. A322662). The subsequences L_n = {a(2^n), a(2^n+1), ... a(2^(n+1)-1)} appear to approach a limit sequence L_{oo}, starting with 4 ON cells. Of these 4, one is a "pioneer" at distance d*2^n from the origin, with d the distance of one knight step. The other three of four ON cells are due to retrogressive growth.

Examples

			Written as a 2^k triangle:
1,
1, 7,
1, 6,  11, 14,
3, 11, 14, 25, 5,  18, 21, 37,
4, 11, 21, 50, 17, 31, 50, 50, 13, 32, 39, 70,  10, 42, 41, 81,
4, 11, 21, 50, 24, 57, 74, 89, 40, 62, 84, 105, 48, 66, 85, 111, ...
		

Crossrefs

Hexagonal: A151724, A170898, A256537. Square: A147582, A147610, A048883; A319019, A322050, A322049. Lower Bound: A038573.

Programs

  • Mathematica
    HexStar=2*Sqrt[3]*{Cos[#*Pi/3+Pi/6],Sin[#*Pi/3+Pi/6]}&/@Range[0,5];
    MoveSet2 =Join[2*HexStar+RotateRight[HexStar],2*HexStar+RotateLeft[HexStar]];
    Clear@Pts;Pts[0] = {{0, 0}};
    Pts[n_]:=Pts[n]=With[{pts=Pts[n-1]},Union[pts,Cases[Tally[Flatten[pts/.{x_,y_}:> Evaluate[{x,y}+#&/@MoveSet2],1]],{x_,1}:>x]]];
    Abs[(1/12)*Subtract@@#&/@Partition[Length[Pts[#]]&/@Range[0,32],2,1]]

Formula

a(n) = (A322662(n)-A322662(n-1))/12.
Previous Showing 11-14 of 14 results.