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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A162795 Total number of toothpicks in the toothpick structure A139250 that are parallel to the initial toothpick, after n odd rounds.

Original entry on oeis.org

1, 5, 9, 21, 25, 37, 53, 85, 89, 101, 117, 149, 165, 201, 261, 341, 345, 357, 373, 405, 421, 457, 517, 597, 613, 649, 709, 793, 853, 965, 1173, 1365, 1369, 1381, 1397, 1429, 1445, 1481, 1541, 1621, 1637, 1673, 1733, 1817, 1877, 1989, 2197, 2389, 2405, 2441, 2501
Offset: 1

Views

Author

Omar E. Pol, Jul 14 2009

Keywords

Comments

Partial sums of A162793.
Also, total number of ON cells at stage n of the two-dimensional cellular automaton defined as follows: replace every "vertical" toothpick of length 2 with a centered unit square "ON" cell, so we have a cellular automaton which is similar to both A147562 and A169707 (this is the "one-step bishop" version). For the "one-step rook" version we use toothpicks of length sqrt(2), then rotate the structure 45 degrees and then replace every toothpick with a unit square "ON" cell. For the illustration of the sequence as a cellular automaton we now have three versions: the original version with toothpicks, the one-step rook version and one-step bishop version. Note that the last two versions refer to the standard ON cells in the same way as the two versions of A147562 and the two versions of A169707. It appears that the graph of this sequence lies between the graphs of A147562 and A169707. Also, it appears that this sequence shares infinitely many terms with both A147562 and A169707, see Formula section and Example section. - Omar E. Pol, Feb 20 2015
It appears that this is also a bisection (the odd terms) of A255747.

Examples

			From _Omar E. Pol_, Feb 18 2015: (Start)
Written as an irregular triangle T(j,k), k>=1, in which the row lengths are the terms of A011782:
    1;
    5;
    9, 21;
   25, 37, 53, 85;
   89,101,117,149,165,201,261,341;
  345,357,373,405,421,457,517,597,613,649,709,793,853,965,1173,1365;
  ...
The right border gives the positive terms of A002450.
(End)
It appears that T(j,k) = A147562(j,k) = A169707(j,k), if k is a power of 2, for example: it appears that the three mentioned triangles only share the elements of the columns 1, 2, 4, 8, 16, ... - _Omar E. Pol_, Feb 20 2015
		

Crossrefs

Formula

It appears that a(n) = A147562(n) = A169707(n), if n is a term of A048645, otherwise A147562(n) < a(n) < A169707(n). - Omar E. Pol, Feb 20 2015
It appears that a(n) = (A169707(2n) - 1)/4 = A255747(2n-1). - Omar E. Pol, Mar 07 2015
a(n) = 1 + 4*A255737(n-1). - Omar E. Pol, Mar 08 2015

Extensions

More terms from N. J. A. Sloane, Dec 28 2009

A118977 a(0)=0, a(1)=1; a(2^i+j) = a(j) + a(j+1) for 0 <= j < 2^i.

Original entry on oeis.org

0, 1, 1, 2, 1, 2, 3, 3, 1, 2, 3, 3, 3, 5, 6, 4, 1, 2, 3, 3, 3, 5, 6, 4, 3, 5, 6, 6, 8, 11, 10, 5, 1, 2, 3, 3, 3, 5, 6, 4, 3, 5, 6, 6, 8, 11, 10, 5, 3, 5, 6, 6, 8, 11, 10, 7, 8, 11, 12, 14, 19, 21, 15, 6, 1, 2, 3, 3, 3, 5, 6, 4, 3, 5, 6, 6, 8, 11, 10, 5, 3, 5, 6, 6, 8, 11, 10, 7, 8, 11, 12, 14, 19, 21, 15
Offset: 0

Views

Author

Gary W. Adamson, May 07 2006

Keywords

Comments

The original definition from Gary W. Adamson: Iterative sequence in 2^n subsets generated from binomial transform operations. Let S = a string s(1) through s(2^n); and B = appended string. Say S = (1, 1, 2, 1). Perform the binomial transform operation on S as a vector: [1, 1, 2, 1, 0, 0, 0, ...] = 1, 2, 5, 11, 21, 36, ... Then, performing the analogous operation on B gives a truncated version of the previous sequence: (2, 5, 11, 21, ...). Given a subset s(1) through s(2^n), say s(1), ..., s(4) = (a,b,c,d). Use the operation ((a+b), (b+c), (c+d), d) and append the result to the right of the previous string. Perform the next operation on s(1) through s(2^(n+1)). s(1), ..., s(4) = (1, 1, 2, 1). The operation gives ((1+1), (1+2), (2+1), (1)) = (2, 3, 3, 1) which we append to (1, 1, 2, 1), giving s(1) through s(8): (1, 1, 2, 1, 2, 3, 3, 1).

Examples

			From _N. J. A. Sloane_, Jun 01 2009: (Start)
Has a natural structure as a triangle:
  0,
  1,
  1,2,
  1,2,3,3,
  1,2,3,3,3,5,6,4,
  1,2,3,3,3,5,6,4,3,5,6,6,8,11,10,5,
  1,2,3,3,3,5,6,4,3,5,6,6,8,11,10,5,3,5,6,6,8,11,10,7,8,11,12,14,19,21,15,6,
  1,2,3,3,3,5,6,4,3,5,...
In this form the rows converge to (1 followed by A160573) or A151687. (End)
		

Crossrefs

For the recurrence a(2^i+j) = C*a(j) + D*a(j+1), a(0) = A, a(1) = B for following values of (A B C D) see: (0 1 1 1) A118977, (1 0 1 1) A151702, (1 1 1 1) A151570, (1 2 1 1) A151571, (0 1 1 2) A151572, (1 0 1 2) A151703, (1 1 1 2) A151573, (1 2 1 2) A151574, (0 1 2 1) A160552, (1 0 2 1) A151704, (1 1 2 1) A151568, (1 2 2 1) A151569, (0 1 2 2) A151705, (1 0 2 2) A151706, (1 1 2 2) A151707, (1 2 2 2) A151708.
Cf. A163267 (partial sums). - N. J. A. Sloane, Jan 07 2010

Programs

  • Maple
    Maple code for the rows of the triangle (PP(n) is a g.f. for the (n+1)-st row):
    g:=n->1+x^(2^n-1)+x^(2^n);
    c:=n->x^(2^n-1)*(1-x^(2^n));
    PP:=proc(n) option remember; global g,c;
    if n=1 then 1+2*x else series(g(n-1)*PP(n-1)-c(n-1),x,10000); fi; end; # N. J. A. Sloane, Jun 01 2009
  • Mathematica
    a[0] = 0; a[1] = 1; a[n_] := a[n] = (j = n - 2^Floor[Log[2, n]]; a[j] + a[j + 1]); Array[a, 95, 0] (* Jean-François Alcover, Nov 10 2016 *)

Formula

a(0)=0; a(2^i)=1. For n >= 3 let n = 2^i + j, where 1 <= j < 2^i. Then a(n) = Sum_{k >= 0} binomial( wt(j+k),k ), where wt() = A000120(). - N. J. A. Sloane, Jun 01 2009
G.f.: ( x + x^2 * Product_{ n >= 0} (1 + x^(2^n-1) + x^(2^n)) ) / (1+x). - N. J. A. Sloane, Jun 08 2009

Extensions

New definition and more terms from N. J. A. Sloane, May 25 2009

A151702 a(0)=1, a(1)=0; a(2^i + j) = a(j) + a(j+1) for 0 <= j < 2^i.

Original entry on oeis.org

1, 0, 1, 1, 1, 1, 2, 2, 1, 1, 2, 2, 2, 3, 4, 3, 1, 1, 2, 2, 2, 3, 4, 3, 2, 3, 4, 4, 5, 7, 7, 4, 1, 1, 2, 2, 2, 3, 4, 3, 2, 3, 4, 4, 5, 7, 7, 4, 2, 3, 4, 4, 5, 7, 7, 5, 5, 7, 8, 9, 12, 14, 11, 5, 1, 1, 2, 2, 2, 3, 4, 3, 2, 3, 4, 4, 5, 7, 7, 4, 2, 3, 4, 4, 5, 7, 7, 5, 5, 7, 8, 9, 12, 14, 11, 5, 2, 3, 4, 4, 5, 7, 7
Offset: 0

Views

Author

N. J. A. Sloane, Jun 06 2009

Keywords

Crossrefs

For the recurrence a(2^i+j) = C*a(j) + D*a(j+1), a(0) = A, a(1) = B for following values of (A B C D) see: (0 1 1 1) A118977, (1 0 1 1) A151702, (1 1 1 1) A151570, (1 2 1 1) A151571, (0 1 1 2) A151572, (1 0 1 2) A151703, (1 1 1 2) A151573, (1 2 1 2) A151574, (0 1 2 1) A160552, (1 0 2 1) A151704, (1 1 2 1) A151568, (1 2 2 1) A151569, (0 1 2 2) A151705, (1 0 2 2) A151706, (1 1 2 2) A151707, (1 2 2 2) A151708.
If first two terms are dropped, same as A151552.

Programs

  • Maple
    f:=proc(r,s,a,b) local s1,n,i,j;
    s1:=array(0..120);
    s1[0]:=r; s1[1]:=s;
    for n from 2 to 120 do i:=floor(log(n)/log(2));
    j:=n-2^i; s1[n]:=a*s1[j]+b*s1[j+1]; od:
    [seq(s1[n],n=0..120)];
    end;
    f(1,0,1,1);
  • Mathematica
    a = {1, 0}; Do[AppendTo[a, a[[j]] + a[[j + 1]]], {i, 6}, {j, 2^i}]; a (* Ivan Neretin, Jun 28 2017 *)

A151703 a(0)=1, a(1)=0; a(2^i+j) = a(j) + 2*a(j+1) for 0 <= j < 2^i.

Original entry on oeis.org

1, 0, 1, 2, 1, 2, 5, 4, 1, 2, 5, 4, 5, 12, 13, 6, 1, 2, 5, 4, 5, 12, 13, 6, 5, 12, 13, 14, 29, 38, 25, 8, 1, 2, 5, 4, 5, 12, 13, 6, 5, 12, 13, 14, 29, 38, 25, 8, 5, 12, 13, 14, 29, 38, 25, 16, 29, 38, 41, 72, 105, 88, 41, 10, 1, 2, 5, 4, 5, 12, 13, 6, 5, 12, 13, 14, 29, 38, 25, 8, 5, 12, 13, 14
Offset: 0

Views

Author

N. J. A. Sloane, Jun 06 2009

Keywords

Crossrefs

For the recurrence a(2^i+j) = C*a(j) + D*a(j+1), a(0) = A, a(1) = B for following values of (A B C D) see: (0 1 1 1) A118977, (1 0 1 1) A151702, (1 1 1 1) A151570, (1 2 1 1) A151571, (0 1 1 2) A151572, (1 0 1 2) A151703, (1 1 1 2) A151573, (1 2 1 2) A151574, (0 1 2 1) A160552, (1 0 2 1) A151704, (1 1 2 1) A151568, (1 2 2 1) A151569, (0 1 2 2) A151705, (1 0 2 2) A151706, (1 1 2 2) A151707, (1 2 2 2) A151708.
If first two terms are dropped, same as A151691.

Programs

  • Maple
    See A151702 for Maple code.
  • Mathematica
    a = {1, 0}; Do[AppendTo[a, a[[j]] + 2 a[[j + 1]]], {i, 6}, {j, 2^i}]; a (* Ivan Neretin, Jul 04 2017 *)

A151568 a(0)=1, a(1)=1; a(2^i+j)=2*a(j)+a(j+1) for 0 <= j < 2^i.

Original entry on oeis.org

1, 1, 3, 5, 3, 5, 11, 13, 3, 5, 11, 13, 11, 21, 35, 29, 3, 5, 11, 13, 11, 21, 35, 29, 11, 21, 35, 37, 43, 77, 99, 61, 3, 5, 11, 13, 11, 21, 35, 29, 11, 21, 35, 37, 43, 77, 99, 61, 11, 21, 35, 37, 43, 77, 99, 69, 43, 77, 107, 117, 163, 253, 259, 125, 3, 5, 11, 13, 11, 21, 35, 29, 11
Offset: 0

Views

Author

N. J. A. Sloane, May 25 2009

Keywords

Comments

Crossrefs

For the recurrence a(2^i+j) = C*a(j) + D*a(j+1), a(0) = A, a(1) = B for following values of (A B C D) see: (0 1 1 1) A118977, (1 0 1 1) A151702, (1 1 1 1) A151570, (1 2 1 1) A151571, (0 1 1 2) A151572, (1 0 1 2) A151703, (1 1 1 2) A151573, (1 2 1 2) A151574, (0 1 2 1) A160552, (1 0 2 1) A151704, (1 1 2 1) A151568, (1 2 2 1) A151569, (0 1 2 2) A151705, (1 0 2 2) A151706, (1 1 2 2) A151707, (1 2 2 2) A151708.

Programs

  • Mathematica
    a = {1, 1}; Do[AppendTo[a, 2 a[[j]] + a[[j + 1]]], {i, 6}, {j, 2^i}]; a (* Ivan Neretin, Jul 04 2017 *)

A151569 a(0)=1, a(1)=2; a(2^i+j)=2*a(j)+a(j+1) for 0 <= j < 2^i.

Original entry on oeis.org

1, 2, 4, 8, 4, 8, 16, 20, 4, 8, 16, 20, 16, 32, 52, 44, 4, 8, 16, 20, 16, 32, 52, 44, 16, 32, 52, 56, 64, 116, 148, 92, 4, 8, 16, 20, 16, 32, 52, 44, 16, 32, 52, 56, 64, 116, 148, 92, 16, 32, 52, 56, 64, 116, 148, 104, 64, 116, 160, 176, 244, 380, 388, 188, 4, 8, 16, 20, 16, 32, 52
Offset: 0

Views

Author

N. J. A. Sloane, May 25 2009

Keywords

Comments

Equals 2*A160552+A151704.

Crossrefs

For the recurrence a(2^i+j) = C*a(j) + D*a(j+1), a(0) = A, a(1) = B for following values of (A B C D) see: (0 1 1 1) A118977, (1 0 1 1) A151702, (1 1 1 1) A151570, (1 2 1 1) A151571, (0 1 1 2) A151572, (1 0 1 2) A151703, (1 1 1 2) A151573, (1 2 1 2) A151574, (0 1 2 1) A160552, (1 0 2 1) A151704, (1 1 2 1) A151568, (1 2 2 1) A151569, (0 1 2 2) A151705, (1 0 2 2) A151706, (1 1 2 2) A151707, (1 2 2 2) A151708.

Programs

  • Mathematica
    a = {1, 2}; Do[AppendTo[a, 2 a[[j]] + a[[j + 1]]], {i, 6}, {j, 2^i}]; a (* Ivan Neretin, Jul 04 2017 *)

A151570 a(0)=1, a(1)=1; a(2^i + j) = a(j) + a(j+1) for 0 <= j < 2^i.

Original entry on oeis.org

1, 1, 2, 3, 2, 3, 5, 5, 2, 3, 5, 5, 5, 8, 10, 7, 2, 3, 5, 5, 5, 8, 10, 7, 5, 8, 10, 10, 13, 18, 17, 9, 2, 3, 5, 5, 5, 8, 10, 7, 5, 8, 10, 10, 13, 18, 17, 9, 5, 8, 10, 10, 13, 18, 17, 12, 13, 18, 20, 23, 31, 35, 26, 11, 2, 3, 5, 5, 5, 8, 10, 7, 5, 8, 10, 10, 13, 18, 17, 9, 5, 8, 10, 10, 13, 18, 17, 12
Offset: 0

Views

Author

N. J. A. Sloane, May 25 2009

Keywords

Comments

Equals A118977 + A151702.

Crossrefs

For the recurrence a(2^i+j) = C*a(j) + D*a(j+1), a(0) = A, a(1) = B for following values of (A B C D) see: (0 1 1 1) A118977, (1 0 1 1) A151702, (1 1 1 1) A151570, (1 2 1 1) A151571, (0 1 1 2) A151572, (1 0 1 2) A151703, (1 1 1 2) A151573, (1 2 1 2) A151574, (0 1 2 1) A160552, (1 0 2 1) A151704, (1 1 2 1) A151568, (1 2 2 1) A151569, (0 1 2 2) A151705, (1 0 2 2) A151706, (1 1 2 2) A151707, (1 2 2 2) A151708.

Programs

  • Mathematica
    a = {1, 1}; Do[AppendTo[a, a[[j]] + a[[j + 1]]], {i, 6}, {j, 2^i}]; a (* Ivan Neretin, Jun 28 2017 *)

A151571 a(0)=1, a(1)=2; a(2^i + j) = a(j) + a(j+1) for 0 <= j < 2^i.

Original entry on oeis.org

1, 2, 3, 5, 3, 5, 8, 8, 3, 5, 8, 8, 8, 13, 16, 11, 3, 5, 8, 8, 8, 13, 16, 11, 8, 13, 16, 16, 21, 29, 27, 14, 3, 5, 8, 8, 8, 13, 16, 11, 8, 13, 16, 16, 21, 29, 27, 14, 8, 13, 16, 16, 21, 29, 27, 19, 21, 29, 32, 37, 50, 56, 41, 17, 3, 5, 8, 8, 8, 13, 16, 11, 8, 13, 16, 16, 21, 29, 27, 14, 8, 13
Offset: 0

Views

Author

N. J. A. Sloane, May 25 2009

Keywords

Comments

Equals 2*A118977 + A151702.

Crossrefs

For the recurrence a(2^i+j) = C*a(j) + D*a(j+1), a(0) = A, a(1) = B for following values of (A B C D) see: (0 1 1 1) A118977, (1 0 1 1) A151702, (1 1 1 1) A151570, (1 2 1 1) A151571, (0 1 1 2) A151572, (1 0 1 2) A151703, (1 1 1 2) A151573, (1 2 1 2) A151574, (0 1 2 1) A160552, (1 0 2 1) A151704, (1 1 2 1) A151568, (1 2 2 1) A151569, (0 1 2 2) A151705, (1 0 2 2) A151706, (1 1 2 2) A151707, (1 2 2 2) A151708.

Programs

  • Mathematica
    a = {1, 2}; Do[AppendTo[a, a[[j]] + a[[j + 1]]], {i, 6}, {j, 2^i}]; a (* Ivan Neretin, Jun 28 2017 *)

A151572 a(0)=0, a(1)=1; a(2^i + j) = a(j) + 2*a(j+1) for 0 <= j < 2^i.

Original entry on oeis.org

0, 1, 2, 5, 2, 5, 12, 9, 2, 5, 12, 9, 12, 29, 30, 13, 2, 5, 12, 9, 12, 29, 30, 13, 12, 29, 30, 33, 70, 89, 56, 17, 2, 5, 12, 9, 12, 29, 30, 13, 12, 29, 30, 33, 70, 89, 56, 17, 12, 29, 30, 33, 70, 89, 56, 37, 70, 89, 96, 173, 248, 201, 90, 21, 2, 5, 12, 9, 12, 29, 30, 13, 12, 29, 30, 33, 70
Offset: 0

Views

Author

N. J. A. Sloane, May 25 2009

Keywords

Crossrefs

For the recurrence a(2^i+j) = C*a(j) + D*a(j+1), a(0) = A, a(1) = B for following values of (A B C D) see: (0 1 1 1) A118977, (1 0 1 1) A151702, (1 1 1 1) A151570, (1 2 1 1) A151571, (0 1 1 2) A151572, (1 0 1 2) A151703, (1 1 1 2) A151573, (1 2 1 2) A151574, (0 1 2 1) A160552, (1 0 2 1) A151704, (1 1 2 1) A151568, (1 2 2 1) A151569, (0 1 2 2) A151705, (1 0 2 2) A151706, (1 1 2 2) A151707, (1 2 2 2) A151708.

Programs

  • Mathematica
    a = {0, 1}; Do[AppendTo[a, a[[j]] + 2 a[[j + 1]]], {i, 6}, {j, 2^i}]; a (* Ivan Neretin, Jun 28 2017 *)

A151573 a(0)=1, a(1)=1; a(2^i + j) = a(j) + 2*a(j+1) for 0 <= j < 2^i.

Original entry on oeis.org

1, 1, 3, 7, 3, 7, 17, 13, 3, 7, 17, 13, 17, 41, 43, 19, 3, 7, 17, 13, 17, 41, 43, 19, 17, 41, 43, 47, 99, 127, 81, 25, 3, 7, 17, 13, 17, 41, 43, 19, 17, 41, 43, 47, 99, 127, 81, 25, 17, 41, 43, 47, 99, 127, 81, 53, 99, 127, 137, 245, 353, 289, 131, 31, 3, 7, 17, 13, 17, 41, 43, 19, 17
Offset: 0

Views

Author

N. J. A. Sloane, May 25 2009

Keywords

Comments

Equals A151572 + A151703.

Crossrefs

For the recurrence a(2^i+j) = C*a(j) + D*a(j+1), a(0) = A, a(1) = B for following values of (A B C D) see: (0 1 1 1) A118977, (1 0 1 1) A151702, (1 1 1 1) A151570, (1 2 1 1) A151571, (0 1 1 2) A151572, (1 0 1 2) A151703, (1 1 1 2) A151573, (1 2 1 2) A151574, (0 1 2 1) A160552, (1 0 2 1) A151704, (1 1 2 1) A151568, (1 2 2 1) A151569, (0 1 2 2) A151705, (1 0 2 2) A151706, (1 1 2 2) A151707, (1 2 2 2) A151708.

Programs

  • Maple
    N:= 10: # to get a(0) to a(2^(N+1)-1)
    a[0]:= 1:
    a[1]:= 1:
    for i from 1 to N do
      for j from 0 to 2^i-1 do
        a[2^i+j]:= a[j]+2*a[j+1]
      od
    od:
    seq(a[i],i=0..2^(N+1)-1); # Robert Israel, May 28 2014
  • Mathematica
    a = {1, 1}; Do[AppendTo[a, a[[j]] + 2 a[[j + 1]]], {i, 6}, {j, 2^i}]; a (* Ivan Neretin, Jun 28 2017 *)
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