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 21 results. Next

A144172 Eigentriangle, row sums = A076739, the number of compositions into Fibonacci numbers.

Original entry on oeis.org

1, 1, 1, 1, 1, 2, 0, 1, 2, 4, 1, 0, 2, 4, 7, 0, 1, 0, 4, 7, 14, 0, 0, 2, 0, 7, 14, 26, 1, 0, 0, 4, 0, 14, 26, 49, 0, 1, 0, 0, 7, 0, 26, 49, 94, 0, 0, 2, 0, 0, 14, 0, 49, 94, 177, 0, 0, 0, 4, 0, 0, 26, 0, 94, 177, 336, 0, 0, 0, 0, 7, 0, 0, 49, 0, 177, 336, 637
Offset: 1

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Author

Gary W. Adamson, Sep 12 2008

Keywords

Comments

Row sums = A076739 starting with offset 1: (1, 2, 4, 7, 14, 26, 49,...).
Left border = A010056, the characteristic function of the Fibonacci numbers Starting with offset 1: (1, 1, 1, 0, 1,...).
Sum of n-th row terms = rightmost term of next row.
Right border = A076739.

Examples

			First few rows of the triangle =
1;
1, 1;
1, 1, 2;
0, 1, 2, 4;
1, 0, 2, 4, 7;
0, 1, 0, 4, 7, 14;
0, 0, 2, 0, 7, 14, 26;
1, 0, 0, 4, 0, 14, 26, 49;
0, 1, 0, 0, 7, 0, 26, 49, 94;
0, 0, 2, 0, 0, 14, 0, 49, 94, 177;
0, 0, 0, 4, 0, 0, 26, 0, 94, 177, 336;
0, 0, 0, 0, 7, 0, 0, 49, 0, 177, 336, 637;
1, 0, 0, 0, 0, 14, 0, 0, 94, 0, 336, 637, 1206;
...
Example: row 5 = (1, 0, 2, 4, 7) = termwise product of (1, 0, 1, 1, 1) and (1, 1, 2, 4, 7).
		

Crossrefs

Formula

T(n,k) = A010056(n-k+1)*A076739(k-1). A010056, the characteristic function of the Fibonacci numbers, starts with offset 1: (1, 1, 1, 0, 1,...). A076739(k-1), the INVERTi transform of (1, 1, 1, 0, 1,...) starts with offset 0: (1, 1, 2, 4, 7, 14,...).

A121548 Triangle read by rows: T(n,k) is the number of compositions of n into k Fibonacci numbers (1 <= k <= n; only one 1 is considered as a Fibonacci number).

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 0, 3, 3, 1, 1, 2, 6, 4, 1, 0, 3, 7, 10, 5, 1, 0, 2, 9, 16, 15, 6, 1, 1, 2, 9, 23, 30, 21, 7, 1, 0, 2, 10, 28, 50, 50, 28, 8, 1, 0, 3, 9, 34, 71, 96, 77, 36, 9, 1, 0, 2, 12, 36, 95, 156, 168, 112, 45, 10, 1, 0, 0, 12, 43, 115, 231, 308, 274, 156, 55, 11, 1, 1, 2, 9, 48, 140, 312, 504, 560, 423, 210, 66, 12, 1
Offset: 1

Views

Author

Emeric Deutsch, Aug 07 2006

Keywords

Examples

			T(5,3)=6 because we have [1,2,2], [2,1,2], [2,2,1], [1,1,3], [1,3,1] and [3,1,1].
Triangle starts:
  1;
  1,  1;
  1,  2,  1;
  0,  3,  3,  1;
  1,  2,  6,  4,  1;
  0,  3,  7, 10,  5,  1;
  0,  2,  9, 16, 15,  6,  1;
  ...
		

Crossrefs

T(2n,n) gives A341072.

Programs

  • Maple
    with(combinat): G:=1/(1-t*sum(z^fibonacci(i),i=2..40))-1: Gser:=simplify(series(G,z=0,25)): for n from 1 to 23 do P[n]:=sort(coeff(Gser,z,n)) od: for n from 1 to 15 do seq(coeff(P[n],t,j),j=1..n) od; # yields sequence in triangular form
    # second Maple program:
    g:= proc(n) g(n):= (t-> issqr(t+4) or issqr(t-4))(5*n^2) end:
    T:= proc(n, t) option remember;
          `if`(n=0, `if`(t=0, 1, 0), `if`(t<1, 0, add(
          `if`(g(j), T(n-j, t-1), 0), j=1..n)))
        end:
    seq(seq(T(n, k), k=1..n), n=1..14); # Alois P. Heinz, Oct 10 2022
  • Mathematica
    nmax = 14;
    T = Rest@CoefficientList[#, t]& /@ Rest@(1/(1 - t*Sum[z^Fibonacci[i],
         {i, 2, nmax}]) - 1 + O[z]^(nmax+1) // CoefficientList[#, z]&);
    Table[T[[n, k]], {n, 1, nmax}, {k, 1, n}] // Flatten (* Jean-François Alcover, May 02 2022 *)

Formula

G.f.: G(t,z) = 1 / (1 - t*Sum_{i>=2} z^Fibonacci(i)) - 1.
Sum of terms in row n = A076739(n).
T(n,1) = A010056(n) (the characteristic function of the Fibonacci numbers);
T(n,2) = A121549(n);
T(n,3) = A121550(n);
Sum_{k=1..n} k*T(n,k) = A121551(n).

A357688 Number of ways to write n as an ordered sum of four positive Fibonacci numbers (with a single type of 1).

Original entry on oeis.org

1, 4, 10, 16, 23, 28, 34, 36, 43, 48, 50, 48, 50, 56, 58, 64, 67, 60, 58, 52, 64, 64, 70, 68, 70, 76, 70, 72, 79, 60, 60, 48, 58, 68, 60, 84, 80, 64, 82, 64, 82, 88, 66, 76, 66, 64, 84, 60, 79, 60, 24, 60, 36, 60, 74, 48, 88, 76, 72, 96, 68, 88, 76, 48, 82, 60, 70
Offset: 4

Views

Author

Ilya Gutkovskiy, Oct 10 2022

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 70; CoefficientList[Series[Sum[x^Fibonacci[k], {k, 2, 21}]^4, {x, 0, nmax}], x] // Drop[#, 4] &

Formula

G.f.: ( Sum_{k>=2} x^Fibonacci(k) )^4.
a(n) = A121548(n,4).

A357690 Number of ways to write n as an ordered sum of five positive Fibonacci numbers (with a single type of 1).

Original entry on oeis.org

1, 5, 15, 30, 50, 71, 95, 115, 140, 165, 191, 205, 220, 240, 260, 285, 310, 325, 325, 320, 341, 350, 380, 385, 405, 420, 430, 450, 465, 465, 445, 410, 435, 425, 450, 481, 495, 515, 490, 510, 555, 525, 580, 540, 530, 570, 530, 580, 600, 520, 525, 440, 455, 520, 445, 555, 530
Offset: 5

Views

Author

Ilya Gutkovskiy, Oct 10 2022

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 61; CoefficientList[Series[Sum[x^Fibonacci[k], {k, 2, 21}]^5, {x, 0, nmax}], x] // Drop[#, 5] &

Formula

G.f.: ( Sum_{k>=2} x^Fibonacci(k) )^5.
a(n) = A121548(n,5).

A357691 Number of ways to write n as an ordered sum of six positive Fibonacci numbers (with a single type of 1).

Original entry on oeis.org

1, 6, 21, 50, 96, 156, 231, 312, 405, 506, 621, 726, 828, 930, 1041, 1160, 1290, 1422, 1520, 1590, 1677, 1766, 1887, 1980, 2106, 2196, 2310, 2426, 2550, 2670, 2706, 2700, 2736, 2756, 2850, 2916, 3071, 3156, 3186, 3296, 3396, 3510, 3621, 3636, 3765, 3720, 3840, 3966, 4010
Offset: 6

Views

Author

Ilya Gutkovskiy, Oct 10 2022

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 54; CoefficientList[Series[Sum[x^Fibonacci[k], {k, 2, 21}]^6, {x, 0, nmax}], x] // Drop[#, 6] &

Formula

G.f.: ( Sum_{k>=2} x^Fibonacci(k) )^6.
a(n) = A121548(n,6).

A218396 Number of compositions of n into distinct (nonzero) Fibonacci numbers.

Original entry on oeis.org

1, 1, 1, 3, 2, 3, 8, 2, 9, 8, 8, 32, 6, 9, 32, 8, 38, 30, 32, 150, 6, 33, 32, 32, 158, 30, 38, 174, 30, 176, 150, 150, 870, 24, 33, 152, 32, 182, 150, 158, 894, 30, 182, 174, 174, 1014, 144, 176, 990, 150, 1014, 864, 870, 5904, 24, 153, 152, 152, 902, 150, 182, 1014, 150, 1022, 894, 894, 6054, 144
Offset: 0

Views

Author

Joerg Arndt, Oct 28 2012

Keywords

Examples

			There are a(37)=182 such compositions of 37. Each of the 6 partitions of 37 into distinct Fibonacci numbers corresponds to m! compositions (where m is the number of parts):
  #:  partition      ( m! compositions)
  1:  1 2 5 8 21     (120 compositions)
  2:  1 2 13 21      ( 24 compositions)
  3:  1 2 34         (  6 compositions)
  4:  3 5 8 21       ( 24 compositions)
  5:  3 13 21        (  6 compositions)
  6:  3 34           (  2 compositions)
The number of compositions is 120 + 24 + 6 + 24 + 6 + 2 = 182.
		

Crossrefs

Cf. A032021 (compositions into distinct odd numbers).
Cf. A000119 (partitions into distinct nonzero Fibonacci numbers), A000700 (partitions into distinct odd numbers).
Cf. A076739 (compositions into Fibonacci numbers).

A359514 Number of compositions (ordered partitions) of n into at most 2 positive Fibonacci numbers (with a single type of 1).

Original entry on oeis.org

1, 1, 2, 3, 3, 3, 3, 2, 3, 2, 3, 2, 0, 3, 2, 2, 3, 0, 2, 0, 0, 3, 2, 2, 2, 0, 3, 0, 0, 2, 0, 0, 0, 0, 3, 2, 2, 2, 0, 2, 0, 0, 3, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 3, 2, 2, 2, 0, 2, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 2, 2, 2, 0, 2
Offset: 0

Views

Author

Ilya Gutkovskiy, Jan 03 2023

Keywords

Crossrefs

Programs

  • Maple
    g:= proc(n) g(n):= (t-> issqr(t+4) or issqr(t-4))(5*n^2) end:
    b:= proc(n, t) option remember; `if`(n=0, 1, `if`(t<1, 0,
          add(`if`(g(j), b(n-j, t-1), 0), j=1..n)))
        end:
    a:= n-> b(n, 2):
    seq(a(n), n=0..94);  # Alois P. Heinz, Jan 03 2023
  • Mathematica
    g[n_] := IntegerQ@Sqrt[# + 4] || IntegerQ@Sqrt[# - 4]&[5 n^2];
    b[n_, t_] := b[n, t] = If[n == 0, 1, If[t < 1, 0, Sum[If[g[j], b[n - j, t - 1], 0], {j, 1, n}]]];
    a[n_] := b[n, 2];
    Table[a[n], {n, 0, 94}] (* Jean-François Alcover, May 26 2023, after Alois P. Heinz *)

Formula

a(n) = Sum_{k=0..2} A121548(n,k). - Alois P. Heinz, Jan 03 2023

A288039 Number of compositions (ordered partitions) of n into Lucas numbers (beginning with 1) (A000204).

Original entry on oeis.org

1, 1, 1, 2, 4, 6, 9, 16, 27, 43, 70, 118, 195, 318, 524, 868, 1430, 2351, 3878, 6399, 10542, 17367, 28634, 47206, 77793, 128212, 211346, 348360, 574153, 946342, 1559849, 2571016, 4237616, 6984659, 11512526, 18975464, 31276187, 51550993, 84968944, 140049801, 230836734, 380476447, 627119783, 1033648857
Offset: 0

Views

Author

Ilya Gutkovskiy, Jun 04 2017

Keywords

Examples

			a(4) = 4 because we have [4], [3, 1], [1, 3] and [1, 1, 1, 1].
		

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[1/(1 - Sum[x^LucasL[k], {k, 1, 15}]), {x, 0, 43}], x]

Formula

G.f.: 1/(1 - Sum_{k>=1} x^A000204(k)).

A357694 Number of ways to write n as an ordered sum of seven positive Fibonacci numbers (with a single type of 1).

Original entry on oeis.org

1, 7, 28, 77, 168, 308, 504, 750, 1050, 1400, 1813, 2261, 2737, 3227, 3753, 4312, 4921, 5579, 6230, 6832, 7413, 8008, 8652, 9289, 9996, 10654, 11361, 12061, 12853, 13657, 14357, 14924, 15393, 15869, 16408, 16933, 17689, 18319, 18949, 19537, 20244, 21049, 21728
Offset: 7

Views

Author

Ilya Gutkovskiy, Oct 10 2022

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 49; CoefficientList[Series[Sum[x^Fibonacci[k], {k, 2, 21}]^7, {x, 0, nmax}], x] // Drop[#, 7] &

Formula

G.f.: ( Sum_{k>=2} x^Fibonacci(k) )^7.
a(n) = A121548(n,7).

A357716 Number of ways to write n as an ordered sum of eight positive Fibonacci numbers (with a single type of 1).

Original entry on oeis.org

1, 8, 36, 112, 274, 560, 1008, 1640, 2479, 3536, 4844, 6392, 8170, 10136, 12308, 14680, 17291, 20160, 23248, 26440, 29674, 32992, 36456, 40040, 43834, 47712, 51752, 55840, 60250, 64856, 69560, 74088, 78331, 82440, 86500, 90616, 95074, 99568, 104188, 108528, 113304
Offset: 8

Views

Author

Ilya Gutkovskiy, Oct 10 2022

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 48; CoefficientList[Series[Sum[x^Fibonacci[k], {k, 2, 21}]^8, {x, 0, nmax}], x] // Drop[#, 8] &

Formula

G.f.: ( Sum_{k>=2} x^Fibonacci(k) )^8.
a(n) = A121548(n,8).
Showing 1-10 of 21 results. Next