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.

A151781 Partial sums of A151779.

Original entry on oeis.org

1, 7, 13, 43, 49, 79, 109, 259, 265, 295, 325, 475, 505, 655, 805, 1555, 1561, 1591, 1621, 1771, 1801, 1951, 2101, 2851, 2881, 3031, 3181, 3931, 4081, 4831, 5581, 9331, 9337, 9367, 9397, 9547, 9577, 9727, 9877, 10627, 10657, 10807, 10957, 11707, 11857, 12607
Offset: 1

Views

Author

N. J. A. Sloane, Jun 25 2009

Keywords

Comments

Total number of ON cells after n-th generation of cellular automaton based on Z^3 lattice in the same way that A147562 is based on the Z^2 lattice. Here each cell has six neighbors.

Crossrefs

Programs

  • Mathematica
    a[n_] := 6*5^(Total@ IntegerDigits[n - 1, 2] - 1); a[1] = 1; Accumulate@ Array[a, 46] (* Michael De Vlieger, Oct 31 2022 *)
  • PARI
    a(n)=sum(k=1,n,6*5^(hammingweight(k-1)-1)\1) \\ Charles R Greathouse IV, Sep 14 2015

A147582 First differences of A147562.

Original entry on oeis.org

1, 4, 4, 12, 4, 12, 12, 36, 4, 12, 12, 36, 12, 36, 36, 108, 4, 12, 12, 36, 12, 36, 36, 108, 12, 36, 36, 108, 36, 108, 108, 324, 4, 12, 12, 36, 12, 36, 36, 108, 12, 36, 36, 108, 36, 108, 108, 324, 12, 36, 36, 108, 36, 108, 108, 324, 36, 108, 108, 324, 108, 324, 324, 972, 4
Offset: 1

Views

Author

N. J. A. Sloane, Apr 29 2009

Keywords

Comments

Bisection of A323651. - Omar E. Pol, Mar 04 2019

Examples

			From _Omar E. Pol_, Jun 14 2009: (Start)
When written as a triangle:
.1;
.4;
.4,12;
.4,12,12,36;
.4,12,12,36,12,36,36,108;
.4,12,12,36,12,36,36,108,12,36,36,108,36,108,108,324;
.4,12,12,36,12,36,36,108,12,36,36,108,36,108,108,324,12,36,36,108,36,108,...
The rows converge to A161411. (End)
		

References

  • D. Singmaster, On the cellular automaton of Ulam and Warburton, M500 Magazine of the Open University, #195 (December 2003), pp. 2-7.
  • S. Ulam, On some mathematical problems connected with patterns of growth of figures, pp. 215-224 of R. E. Bellman, ed., Mathematical Problems in the Biological Sciences, Proc. Sympos. Applied Math., Vol. 14, Amer. Math. Soc., 1962.

Crossrefs

Cf. A147562, A147610 (the sequence divided by 4), A048881, A000120.
Cf. A048883, A139251, A160121, A162349. [Omar E. Pol, Nov 02 2009]
Cf. A323651.

Programs

  • Maple
    A000120 := proc(n) local w,m,i; w := 0; m := n; while m > 0 do i := m mod 2; w := w+i; m := (m-i)/2; od; w; end: wt := A000120; A147582 := n-> if n <= 1 then n else 4*3^(wt(n-1)-1); fi; [seq(A147582(n),n=0..1000)]; # N. J. A. Sloane, Apr 07 2010
  • Mathematica
    s = Plus @@ Flatten@ # & /@ CellularAutomaton[{686, {2, {{0, 2, 0}, {2, 1, 2}, {0, 2, 0}}}, {1, 1}}, {{{1}}, 0}, 200]; f[n_] = If[n == 0, 1, s[[n + 1]] - s[[n]]]; Array[f, 120, 0] (* Michael De Vlieger, Apr 09 2015, after Nadia Heninger and N. J. A. Sloane at A147562 *)

Formula

a(1) = 1; for n > 1, a(n) = 4*3^(wt(n-1)-1) where wt() = A000120(). - R. J. Mathar, Apr 30 2009
This formula is (essentially) given by Singmaster. - N. J. A. Sloane, Aug 06 2009
G.f.: x + 4*x*(Product_{k >= 0} (1 + 3*x^(2^k)) - 1)/3. - N. J. A. Sloane, Jun 10 2009

Extensions

Extended by R. J. Mathar, Apr 30 2009

A255740 Square array read by antidiagonals upwards: T(n,1) = 1; for k > 1, T(n,k) = (n-1)*(n-2)^(A000120(k-1)-1) with n >= 1.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 2, 1, 0, 1, 3, 2, 0, 0, 1, 4, 3, 2, 1, 0, 1, 5, 4, 6, 2, 0, 0, 1, 6, 5, 12, 3, 2, 0, 0, 1, 7, 6, 20, 4, 6, 2, 0, 0, 1, 8, 7, 30, 5, 12, 6, 2, 1, 0, 1, 9, 8, 42, 6, 20, 12, 12, 2, 0, 0, 1, 10, 9, 56, 7, 30, 20, 36, 3, 2, 0, 0, 1, 11, 10, 72, 8, 42, 30, 80, 4, 6, 2, 0, 0, 1, 12, 11, 90, 9, 56, 42, 150, 5, 12, 6, 2, 0, 0
Offset: 1

Views

Author

Omar E. Pol, Mar 05 2015

Keywords

Comments

The partial sums of row n give the n-th row of the square array A255741.

Examples

			The corner of the square array with the first 16 terms of the first 12 rows looks like this:
-------------------------------------------------------------------------
A000007: 1, 0, 0,  0, 0,  0,  0,   0, 0,  0,  0,   0,  0,   0,   0,    0
A255738: 1, 1, 1,  0, 1,  0,  0,   0  1,  0,  0,   0,  0,   0,   0,    0
A040000: 1, 2, 2,  2, 2,  2,  2,   2, 2,  2,  2,   2,  2,   2,   2,    2
A151787: 1, 3, 3,  6, 3,  6,  6,  12, 3,  6,  6,  12,  6,  12,  12,   24
A147582: 1, 4, 4, 12, 4, 12, 12,  36, 4, 12, 12,  36, 12,  36,  36,  108
A151789: 1, 5, 5, 20, 5, 20, 20,  80, 5, 20, 20,  80, 20,  80,  80,  320
A151779: 1, 6, 6, 30, 6, 30, 30, 150, 6, 30, 30, 150, 30, 150, 150,  750
A151791: 1, 7, 7, 42, 7, 42, 42, 252, 7, 42, 42, 252, 42, 252, 252, 1512
A151782: 1, 8, 8, 56, 8, 56, 56, 392, 8, 56, 56, 392, 56, 392, 392, 2744
A255743: 1, 9, 9, 72, 9, 72, 72, 576, 9, 72, 72, 576, 72, 576, 576, 4608
A255744: 1,10,10, 90,10, 90, 90, 810,10, 90, 90, 810, 90, 810, 810, 7290
A255745: 1,11,11,110,11,110,110,1100,11,110,110,1100,110,1100,1100,11000
...
		

Crossrefs

Column 1 is A000012.
Columns 2^k+1, for k >=0: A011477.
Columns 4, 6, 7, 10, 11, 13...: 0 together with A002378.

Programs

  • PARI
    tabl(nn) = {for (n=1, nn, for (k=1, nn, if (k==1, x = 1, x= (n-1)*(n-2)^(hammingweight(k-1)-1)); print1(x, ", ");); print(););} \\ Michel Marcus, Mar 15 2015

Formula

T(n,1) = 1; for k > 1, T(n,k) = (n-1)*(n-2)^(A000120(k-1)-1) with n >= 1.

A151787 a(1)=1; for n > 1, a(n)=3*2^{wt(n-1)-1}.

Original entry on oeis.org

1, 3, 3, 6, 3, 6, 6, 12, 3, 6, 6, 12, 6, 12, 12, 24, 3, 6, 6, 12, 6, 12, 12, 24, 6, 12, 12, 24, 12, 24, 24, 48, 3, 6, 6, 12, 6, 12, 12, 24, 6, 12, 12, 24, 12, 24, 24, 48, 6, 12, 12, 24, 12, 24, 24, 48, 12, 24, 24, 48, 24, 48, 48, 96, 3, 6, 6, 12, 6, 12, 12, 24, 6, 12, 12, 24, 12, 24, 24, 48
Offset: 1

Views

Author

N. J. A. Sloane, Jun 25 2009

Keywords

Comments

wt(n) is the Hamming weight = binary weight of n (A000120).

Crossrefs

Programs

  • Maple
    wt:= n -> convert(convert(n,base,2),`+`):
    [1, seq(3*2^(wt(n-1)-1),n=2..100)]; # Robert Israel, Feb 27 2018
  • Mathematica
    a[n_] := If[n == 1, 1, 3*2^(Total[IntegerDigits[n-1, 2]]-1)];
    Array[a, 100] (* Jean-François Alcover, Mar 27 2019 *)
  • PARI
    a(n) = if (n==1, 1, 3*2^(hammingweight(n-1)-1)); \\ Michel Marcus, Feb 27 2018

Formula

From Robert Israel, Feb 27 2018: (Start)
For n > 1, a(2*n)=2*a(n).
a(2*n+1)=a(n+1).
G.f. g(x) satisfies g(x) = (2+1/x)*g(x^2) + x^2. (End)
a(n) = 3*A001316(n-1)/2 for n >= 2. - Georg Fischer, Jun 23 2021

Extensions

Definition corrected by Omar E. Pol, Mar 03 2015

A151780 a(n) = 5^(wt(n) - 1) where wt(n) = A000120(n).

Original entry on oeis.org

1, 1, 5, 1, 5, 5, 25, 1, 5, 5, 25, 5, 25, 25, 125, 1, 5, 5, 25, 5, 25, 25, 125, 5, 25, 25, 125, 25, 125, 125, 625, 1, 5, 5, 25, 5, 25, 25, 125, 5, 25, 25, 125, 25, 125, 125, 625, 5, 25, 25, 125, 25, 125, 125, 625, 25, 125, 125, 625, 125, 625, 625, 3125, 1, 5, 5, 25, 5, 25, 25, 125, 5
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;
  1,5;
  1,5,5,25;
  1,5,5,25,5,25,25,125;
  1,5,5,25,5,25,25,125,5,25,25,125,25,125,125,625;
  1,5,5,25,5,25,25,125,5,25,25,125,25,125,125,625,5,25,25,125,25,125,125,625,...
(End)
		

Crossrefs

Essentially A151779/6.
Cf. A000351. - Omar E. Pol, Jul 21 2009

Programs

  • PARI
    a(n) = 5^(hammingweight(n)-1); \\ Michel Marcus, Nov 15 2022

A151782 a(1)=1; for n > 1, a(n)=8*7^{wt(n-1)-1}.

Original entry on oeis.org

1, 8, 8, 56, 8, 56, 56, 392, 8, 56, 56, 392, 56, 392, 392, 2744, 8, 56, 56, 392, 56, 392, 392, 2744, 56, 392, 392, 2744, 392, 2744, 2744, 19208, 8, 56, 56, 392, 56, 392, 392, 2744, 56, 392, 392, 2744, 392, 2744, 2744, 19208, 56, 392, 392, 2744, 392, 2744, 2744, 19208, 392
Offset: 1

Views

Author

N. J. A. Sloane, Jun 25 2009

Keywords

Crossrefs

Cf. A151779, A151780, etc.

A255743 a(1) = 1; for n > 1, a(n) = 9*8^{A000120(n-1)-1}.

Original entry on oeis.org

1, 9, 9, 72, 9, 72, 72, 576, 9, 72, 72, 576, 72, 576, 576, 4608, 9, 72, 72, 576, 72, 576, 576, 4608, 72, 576, 576, 4608, 576, 4608, 4608, 36864, 9, 72, 72, 576, 72, 576, 576, 4608, 72, 576, 576, 4608, 576, 4608, 4608, 36864, 72, 576, 576, 4608, 576, 4608, 4608
Offset: 1

Views

Author

Omar E. Pol, Mar 05 2015

Keywords

Comments

Also, this is a row of the square array A255740.
Partial sums give A255764.

Examples

			Written as an irregular triangle in which the row lengths are the terms of A011782, the sequence begins:
   1;
   9;
   9, 72;
   9, 72, 72, 576;
   9, 72, 72, 576, 72, 576, 576, 4608;
   ...
		

Crossrefs

Programs

  • Mathematica
    MapAt[Floor, Array[9*8^(DigitCount[# - 1, 2, 1] - 1) &, 55], 1] (* Michael De Vlieger, Nov 03 2022 *)
  • PARI
    a(n) = if (n==1, 1, 9*8^(hammingweight(n-1)-1)); \\ Michel Marcus, Mar 15 2015
    
  • Python
    # Python 3.10+
    def A255743(n): return 1 if n == 1 else 9*(1<<((n-1).bit_count()-1)*3) # Chai Wah Wu, Nov 15 2022

Extensions

More terms from Michel Marcus, Mar 15 2015

A255744 a(1) = 1; for n > 1, a(n) = 10*9^(A000120(n-1)-1).

Original entry on oeis.org

1, 10, 10, 90, 10, 90, 90, 810, 10, 90, 90, 810, 90, 810, 810, 7290, 10, 90, 90, 810, 90, 810, 810, 7290, 90, 810, 810, 7290, 810, 7290, 7290, 65610, 10, 90, 90, 810, 90, 810, 810, 7290, 90, 810, 810, 7290, 810, 7290, 7290, 65610, 90, 810, 810, 7290, 810, 7290
Offset: 1

Views

Author

Omar E. Pol, Mar 05 2015

Keywords

Comments

Also, this is a row of the square array A255740.
Partial sums give A255765.

Examples

			Also, written as an irregular triangle in which the row lengths are the terms of A011782, the sequence begins:
1;
10;
10, 90;
10, 90, 90, 810;
10, 90, 90, 810, 90, 810, 810, 7290;
...
		

Crossrefs

Programs

  • Mathematica
    MapAt[Floor, Array[10*9^(DigitCount[# - 1, 2, 1] - 1) &, 54], 1] (* Michael De Vlieger, Nov 03 2022 *)
  • PARI
    a(n) = if (n==1, 1, 10*9^(hammingweight(n-1)-1)); \\ Michel Marcus, Mar 15 2015

Extensions

More terms from Michel Marcus, Mar 15 2015

A255745 a(1) = 1; for n > 1, a(n) = 11*10^{A000120(n-1)-1}.

Original entry on oeis.org

1, 11, 11, 110, 11, 110, 110, 1100, 11, 110, 110, 1100, 110, 1100, 1100, 11000, 11, 110, 110, 1100, 110, 1100, 1100, 11000, 110, 1100, 1100, 11000, 1100, 11000, 11000, 110000, 11, 110, 110, 1100, 110, 1100, 1100, 11000, 110, 1100, 1100, 11000, 1100, 11000, 11000
Offset: 1

Views

Author

Omar E. Pol, Mar 05 2015

Keywords

Comments

Also, this is a row of the square array A255740.
Partial sums give A255766.
Is this also A151787 written in base 2?

Examples

			Also, written as an irregular triangle in which the row lengths are the terms of A011782, the sequence begins:
1;
11;
11, 110;
11, 110, 110, 1100;
11, 110, 110, 1100, 110, 1100, 1100, 11000;
...
		

Crossrefs

Programs

  • PARI
    a(n) = if (n==1, 1, 11*10^(hammingweight(n-1)-1)); \\ Michel Marcus, Mar 13 2015

Extensions

More terms from Michel Marcus, Mar 13 2015

A186411 First differences of A186410.

Original entry on oeis.org

0, 1, 5, 5, 21, 5, 21, 21, 101, 5, 21, 21, 101, 21, 101, 101, 501, 5, 21, 21, 101, 21, 101, 101, 501, 21, 101, 101, 501, 101, 501, 501, 2501, 5, 21, 21, 101, 21, 101, 101, 501, 21, 101, 101, 501, 101, 501, 501, 2501, 21, 101, 101, 501, 101, 501, 501, 2501, 101
Offset: 0

Views

Author

Omar E. Pol, Feb 21 2011

Keywords

Comments

Number of cells turned "ON" at h-th stage of the three-dimensional cellular automaton of A186410. In other words: number of cubes added at n-th stage to the structure of A186410.

Crossrefs

Programs

  • Mathematica
    a[n_] := 1 + 4*5^(DigitCount[n-1, 2, 1]-1); a[0] = 0; a[1] = 1; Array[a, 100, 0] (* Amiram Eldar, Aug 01 2023 *)

Formula

a(n) = 1 + 4*5^(A000120(n-1)-1), n >= 2. - Nathaniel Johnston, Mar 22 2011

Extensions

More terms from Nathaniel Johnston, Mar 22 2011
More terms from Amiram Eldar, Aug 01 2023
Showing 1-10 of 10 results.