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 14 results. Next

A099928 Row sums of Pellonomial triangle A099927.

Original entry on oeis.org

1, 2, 4, 12, 56, 408, 4608, 80784, 2201536, 93224736, 6134017792, 627029574336, 99602689462784, 24580813373119872, 9426621978735869952, 5616371724370667073792, 5199854362208758062125056, 7479400854548558531507839488, 16717751433807850998823619411968
Offset: 0

Views

Author

Ralf Stephan, Nov 03 2004

Keywords

Programs

  • Maple
    p:= proc(n) p(n):= `if`(n<2, n, 2*p(n-1)+p(n-2)) end:
    f:= proc(n) f(n):= `if`(n=0, 1, p(n)*f(n-1)) end:
    a:= n-> add(f(n)/(f(k)*f(n-k)), k=0..n):
    seq(a(n), n=0..20);  # Alois P. Heinz, Aug 15 2013
  • Mathematica
    p[n_] := p[n] = If[n < 2, n, 2*p[n - 1] + p[n - 2]];
    f[n_] := f[n] = If[n == 0, 1, p[n]*f[n - 1]];
    T[n_, k_] := f[n]/(f[k]*f[n - k]);
    a[n_] := Sum[T[n, k], {k, 0, n}];
    Table[a[n], {n, 0, 20}] (* Jean-François Alcover, Nov 16 2022, after Alois P. Heinz *)

A383715 Triangle T(n,k), n >= 0, 0 <= k <= n, read by rows, where T(n,k) = (-1)^floor((k+1)/2) * A099927(n,k).

Original entry on oeis.org

1, 1, -1, 1, -2, -1, 1, -5, -5, 1, 1, -12, -30, 12, 1, 1, -29, -174, 174, 29, -1, 1, -70, -1015, 2436, 1015, -70, -1, 1, -169, -5915, 34307, 34307, -5915, -169, 1, 1, -408, -34476, 482664, 1166438, -482664, -34476, 408, 1, 1, -985, -200940, 6791772, 39618670, -39618670, -6791772, 200940, 985, -1
Offset: 0

Views

Author

Seiichi Manyama, May 07 2025

Keywords

Examples

			Triangle starts:
  1;
  1,   -1;
  1,   -2,    -1;
  1,   -5,    -5,     1;
  1,  -12,   -30,    12,     1;
  1,  -29,  -174,   174,    29,    -1;
  1,  -70, -1015,  2436,  1015,   -70,   -1;
  1, -169, -5915, 34307, 34307, -5915, -169, 1;
  ...
		

Crossrefs

Programs

  • PARI
    pell(n) = ([2, 1; 1, 0]^n)[2, 1];
    p(n, k) = prod(j=0, k-1, pell(n-j));
    a099927(n, k) = p(n, k)/p(k, k);
    T(n, k) = (-1)^((k+1)\2)*a099927(n, k);

Formula

Let f(n, x) be defined as f(n, x) = Sum_{k=0..n} T(n,k) * x^k.
f(n, x) = exp( -Sum_{k>=1} Pell(n*k)/Pell(k) * x^k/k ).
Sum_{k>=0} A099927(n+k,n) * x^k = 1/f(n+1, x).

A256799 Catalan number analogs for A099927, the generalized binomial coefficients for Pell numbers (A000129).

Original entry on oeis.org

1, 1, 6, 203, 40222, 46410442, 312163223724, 12237378320283699, 2796071362211148193590, 3723566980632561787914135870, 28901575272390972687956930234335380, 1307480498356321410289575304307661963042110, 344746842780849469098742541704318199701366091840620
Offset: 0

Views

Author

Tom Edgar, Apr 10 2015

Keywords

Comments

One definition of the Catalan numbers is binomial(2*n,n) / (n+1); the current sequence models this definition using the generalized binomial coefficients arising from Pell numbers (A000129).

Examples

			a(5) = Pell(10)..Pell(7)/Pell(5)..Pell(1) = (2378*985*408*169)/(29*12*5*2*1) = 46410442.
a(3) = A099927(6,3)/Pell(3) = 2436/12 = 203.
		

Crossrefs

Programs

  • Maple
    p:= n-> (<<2|1>, <1|0>>^n)[1, 2]:
    a:= n-> mul(p(i), i=n+2..2*n)/mul(p(i), i=1..n):
    seq(a(n), n=0..12);  # Alois P. Heinz, Apr 10 2015
  • Mathematica
    Pell[m_]:=Expand[((1+Sqrt[2])^m-(1-Sqrt[2])^m)/(2*Sqrt[2])]; Table[Product[Pell[k],{k,1,2*n}]/(Product[Pell[k],{k,1,n}])^2 / Pell[n+1],{n,0,15}] (* Vaclav Kotesovec, Apr 10 2015 *)
  • Sage
    P=[lucas_number1(n, 2, -1) for n in [0..30]]
    [1/P[n+1]*prod(P[1:2*n+1])/(prod(P[1:n+1]))^2 for n in [0..14]]

Formula

a(n) = Pell(2n)Pell(2n-1)...Pell(n+2)/Pell(n)Pell(n-1)...Pell(1) = A099927(2*n,n)/Pell(n+1) = A099929(n)/Pell(n+1), where Pell(k) = A000129(k).
a(n) ~ 2^(3/2) * (1+sqrt(2))^(n^2-n-1) / c, where c = A256831 = 1.141982569667791206028... . - Vaclav Kotesovec, Apr 10 2015

A139332 Duplicate of A099927.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 5, 5, 1, 1, 12, 30, 12, 1, 1, 29, 174, 174, 29, 1, 1, 70, 1015, 2436, 1015, 70, 1, 1, 169, 5915, 34307, 34307, 5915, 169, 1, 1, 408, 34476, 482664, 1166438, 482664, 34476, 408, 1, 1, 985, 200940, 6791772, 39618670, 39618670, 6791772, 200940, 985, 1
Offset: 1

Views

Author

Keywords

A010048 Triangle of Fibonomial coefficients, read by rows.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 3, 6, 3, 1, 1, 5, 15, 15, 5, 1, 1, 8, 40, 60, 40, 8, 1, 1, 13, 104, 260, 260, 104, 13, 1, 1, 21, 273, 1092, 1820, 1092, 273, 21, 1, 1, 34, 714, 4641, 12376, 12376, 4641, 714, 34, 1, 1, 55, 1870, 19635, 85085, 136136, 85085, 19635, 1870, 55, 1
Offset: 0

Views

Author

Keywords

Comments

Conjecture: polynomials with (positive) Fibonomial coefficients are reducible iff n odd > 1. - Ralf Stephan, Oct 29 2004

Examples

			First few rows of the triangle T(n, k) are:
  n\k 0   1    2     3     4      5      6      7     8   9  10
   0: 1
   1: 1   1
   2: 1   1    1
   3: 1   2    2     1
   4: 1   3    6     3     1
   5: 1   5   15    15     5      1
   6: 1   8   40    60    40      8      1
   7: 1  13  104   260   260    104     13      1
   8: 1  21  273  1092  1820   1092    273     21     1
   9: 1  34  714  4641 12376  12376   4641    714    34   1
  10: 1  55 1870 19635 85085 136136  85085  19635  1870  55   1
... - Table extended and reformatted by _Wolfdieter Lang_, Oct 10 2012
For n=7 and k=3, n - k + 1 = 7 - 3 + 1 = 5, so T(7,3) = F(7)*F(6)*F(5)/( F(3)*F(2)*F(1)) = 13*8*5/(2*1*1) = 520/2 = 260. - _Michael B. Porter_, Sep 26 2016
		

References

  • A. T. Benjamin and J. J. Quinn, Proofs that really count: the art of combinatorial proof, M.A.A. 2003, p. 15.
  • D. E. Knuth, The Art of Computer Programming. Addison-Wesley, Reading, MA, Vol. 1, p. 84 and 492.

Crossrefs

Cf. A055870 (signed version of triangle).
Sums include: A056569 (row), A181926 (antidiagonal), A181927 (row square-sums).
Cf. A003267 and A003268 (central Fibonomial coefficients), A003150 (Fibonomial Catalan numbers), A144712, A099927, A385732/A385733 (Lucas).

Programs

  • Magma
    Fibonomial:= func< n,k | k eq 0 select 1 else (&*[Fibonacci(n-j+1)/Fibonacci(j): j in [1..k]]) >;
    [Fibonomial(n,k): k in [0..n], n in [0..12]]; // G. C. Greubel, Jul 20 2024
    
  • Maple
    A010048 := proc(n,k)
        mul(combinat[fibonacci](i),i=n-k+1..n)/mul(combinat[fibonacci](i),i=1..k) ;
    end proc:
    seq(seq(A010048(n,k),k=0..n),n=0..10) ; # R. J. Mathar, Feb 05 2015
  • Mathematica
    f[n_, k_] := Product[ Fibonacci[n - j + 1]/Fibonacci[j], {j, k}]; Table[ f[n, i], {n, 0, 10}, {i, 0, n}] (* Robert G. Wilson v, Dec 04 2009 *)
    Column[Round@Table[GoldenRatio^(k(n-k)) QBinomial[n, k, -1/GoldenRatio^2], {n, 0, 10}, {k, 0, n}], Center] (* Round is equivalent to FullSimplify here, but is much faster - Vladimir Reshetnikov, Sep 25 2016 *)
    T[n_, k_] := With[{c = ArcCsch[2] - I Pi/2}, Product[I^j Sinh[c j], {j, k + 1, n}] / Product[I^j Sinh[c j], {j, 1, n - k}]]; Table[Simplify[T[n, k]], {n, 0, 10}, {k, 0, n}] // Flatten  (* Peter Luschny, Jul 08 2025 *)
  • Maxima
    ffib(n):=prod(fib(k),k,1,n);
    fibonomial(n,k):=ffib(n)/(ffib(k)*ffib(n-k));
    create_list(fibonomial(n,k),n,0,20,k,0,n); /* Emanuele Munarini, Apr 02 2012 */
    
  • PARI
    T(n, k) = prod(j=0, k-1, fibonacci(n-j))/prod(j=1, k, fibonacci(j));
    tabl(nn) = for (n=0, nn, for (k=0, n, print1(T(n, k), ", ")); print); \\ Michel Marcus, Jul 20 2018
    
  • SageMath
    def fibonomial(n,k): return 1 if k==0 else product(fibonacci(n-j+1)/fibonacci(j) for j in range(1,k+1))
    flatten([[fibonomial(n,k) for k in range(n+1)] for n in range(13)]) # G. C. Greubel, Jul 20 2024

Formula

T(n, k) = ((n, k)) = (F(n)*F(n-1)*...*F(n-k+1))/(F(k)*F(k-1)*...*F(1)), F(i) = Fibonacci numbers A000045.
T(n, k) = Fibonacci(n-k-1)*T(n-1, k-1) + Fibonacci(k+1)*T(n-1, k).
T(n, k) = phi^(k*(n-k)) * C(n, k)A001622%20is%20the%20golden%20ratio,%20and%20C(n,%20k)_q%20is%20the%20q-binomial%20coefficient.%20-%20_Vladimir%20Reshetnikov">{-1/phi^2}, where phi = (1+sqrt(5))/2 = A001622 is the golden ratio, and C(n, k)_q is the q-binomial coefficient. - _Vladimir Reshetnikov, Sep 26 2016
G.f. of column k: x^k * exp( Sum_{j>=1} Fibonacci((k+1)*j)/Fibonacci(j) * x^j/j ). - Seiichi Manyama, May 07 2025
T(n, k) = Product_{j=k+1..n} i^j*sinh(c*j) / Product_{j=1..n-k} i^j*sinh(c*j) where c = arccsch(2) - i*Pi/2 and i is the imaginary unit. If you substitute sinh by cosh you get the Lucas triangle A385732/A385733, which is a rational triangle. - Peter Luschny, Jul 08 2025

A099929 Central Pellonomial coefficients.

Original entry on oeis.org

1, 2, 30, 2436, 1166438, 3248730940, 52755584809356, 4992850354675749192, 2754130291777980970686150, 8854642279944231931659815098860, 165923943638796574201560736475319416580, 18121679707218614746613513717704194807763644600
Offset: 0

Views

Author

Ralf Stephan, Nov 03 2004

Keywords

Crossrefs

Programs

  • Maple
    p:= proc(n) p(n):= `if`(n<2, n, 2*p(n-1)+p(n-2)) end:
    f:= proc(n) f(n):= `if`(n=0, 1, p(n)*f(n-1)) end:
    a:= n-> f(2*n)/f(n)^2:
    seq(a(n), n=0..15);  # Alois P. Heinz, Aug 15 2013
  • Mathematica
    Pell[m_]:=Expand[((1+Sqrt[2])^m-(1-Sqrt[2])^m)/(2*Sqrt[2])]; Table[Product[Pell[k],{k,1,2*n}]/(Product[Pell[k],{k,1,n}])^2,{n,0,20}] (* Vaclav Kotesovec, Apr 10 2015 *)
  • Sage
    P=[lucas_number1(n, 2, -1) for n in [0..30]]
    [prod(P[1:2*n+1])/(prod(P[1:n+1]))^2 for n in [0..14]] # Tom Edgar, Apr 10 2015
    
  • Sage
    def a(n): return ((1+sqrt(2))^n^2*q_binomial(2*n, n, -(3-2*sqrt(2)))).simplify_full() # Seiichi Manyama, May 10 2025

Formula

a(n) = A099927(2n, n).
a(n) ~ (1+sqrt(2))^(n^2) / c, where c = A256831 = 1.141982569667791206028... . - Vaclav Kotesovec, Apr 10 2015
a(n) = (1 + sqrt(2))^(n^2) * q-binomial(2*n, n, -(sqrt(2) - 1)^2). - Seiichi Manyama, May 10 2025

A099930 a(n) = Pell(n) * Pell(n-1) * Pell(n-2) / 10.

Original entry on oeis.org

1, 12, 174, 2436, 34307, 482664, 6791772, 95567064, 1344731653, 18921807828, 266250046986, 3746422451772, 52716164405255, 741772724044560, 10437534301224120, 146867252940711408, 2066579075472320521, 29078974309550454492, 409172219409185308518, 5757490046038128779316
Offset: 3

Views

Author

Ralf Stephan, Nov 03 2004

Keywords

Crossrefs

Cf. A000129. Third column of triangle A099927. Cf. A001656, A084175.

Programs

  • Mathematica
    Drop[CoefficientList[Series[x^3/((1+2x-x^2)(1-14x-x^2)),{x,0,20}],x],3] (* or *) LinearRecurrence[{12,30,-12,-1},{1,12,174,2436},20] (* Harvey P. Dale, Feb 26 2012 *)

Formula

G.f.: x^3 / ((1+2*x-x^2)*(1-14*x-x^2)).
a(n) = 12*a(n-1) + 30*a(n-2) - 12*a(n-3) - a(n-4); a(3)=1, a(4)=12, a(5)=174, a(6)=2436. - Harvey P. Dale, Feb 26 2012
From Peter Bala, Mar 30 2015: (Start)
The following remarks assume an offset of 0.
The o.g.f. A(x) = 1/( (1 + 2*x - x^2)*(1 - 14*x - x^2) ). Hence A(x) (mod 4) = 1/(1 + 2*x - x^2)^2 (mod 4). It follows by Theorem 1 of Heninger et al. that sqrt(A(x)) = 1 + 6*x + 69*x^2 + 804*x^3 + ... has integral coefficients.
Sum_{n >= 0} a(n+3)*x^n = exp( Sum_{n >= 1} Pell(4*n)/Pell(n)*x^n/n ). Cf. A001656, A084175. (End)
a(n+1) = (1/2)*Sum_{k=1..n-1} ( A014445(k)*A110272(n-k) ) for n > 1. - Michael A. Allen, Jan 25 2023

A099931 a(n) = Pell(n) * Pell(n-1) * Pell(n-2) * Pell(n-3) / 120.

Original entry on oeis.org

1, 29, 1015, 34307, 1166438, 39618670, 1345902818, 45720876202, 1553165059215, 52761884311059, 1792350941301921, 60887169888069525, 2068371426604585180, 70263741326790571820, 2386898833730186862100, 81084296605231967961956, 2754479185745716380504749
Offset: 4

Views

Author

Ralf Stephan, Nov 03 2004

Keywords

Crossrefs

Cf. A000129. Fourth column of triangle A099927.

Formula

G.f.: x^4 / ((1-x)*(1+6x+x^2)*(1-34x+x^2)).
a(n) = 29*a(n-1) + 174*a(n-2) - 174*a(n-3) - 29*a(n-4) + a(n-5). - Klaus Purath, Oct 17 2020
G.f.: x^4 * exp( Sum_{k>=1} Pell(5*k)/Pell(k) * x^k/k ). - Seiichi Manyama, May 07 2025

A172342 Triangle t(n,k) read by rows: fibonomial ratios c(n)/(c(k)*c(n-k)) where c are partial products of a generalized Fibonacci sequence with multiplier m=5.

Original entry on oeis.org

1, 1, 1, 1, 5, 1, 1, 26, 26, 1, 1, 135, 702, 135, 1, 1, 701, 18927, 18927, 701, 1, 1, 3640, 510328, 2649780, 510328, 3640, 1, 1, 18901, 13759928, 370988828, 370988828, 13759928, 18901, 1, 1, 98145, 371007729, 51941082060, 269708877956
Offset: 0

Views

Author

Roger L. Bagula, Feb 01 2010

Keywords

Comments

Start from the generalized Fibonacci sequence A052918 and its partial products c(n) = 1, 1, 5, 130, 17550, 12302550, 44781282000,... Then t(n,k) = c(n)/(c(k)*c(n-k)).
Row sums are 1, 2, 7, 54, 974, 39258, 3677718, 769535316, 374333253826, 406720191959532,...

Examples

			1;
1, 1;
1, 5, 1;
1, 26, 26, 1;
1, 135, 702, 135, 1;
1, 701, 18927, 18927, 701, 1;
1, 3640, 510328, 2649780, 510328, 3640, 1;
1, 18901, 13759928, 370988828, 370988828, 13759928, 18901, 1;
1, 98145, 371007729, 51941082060, 269708877956, 51941082060, 371007729, 98145, 1;
		

Crossrefs

Cf. A010048 (m=1), A099927 (m=2), A172339 (m=3), A172343 (m=6).

Programs

  • Mathematica
    Clear[f, c, a, t];
    f[0, a_] := 0; f[1, a_] := 1;
    f[n_, a_] := f[n, a] = a*f[n - 1, a] + f[n - 2, a];
    c[n_, a_] := If[n == 0, 1, Product[f[i, a], {i, 1, n}]];
    t[n_, m_, a_] := c[n, a]/(c[m, a]*c[n - m, a]);
    Table[Table[Table[t[n, m, a], {m, 0, n}], {n, 0, 10}], {a, 1, 10}];
    Table[Flatten[Table[Table[t[n, m, a], {m, 0, n}], {n, 0, 10}]], {a, 1, 10}]

A172343 Triangle t(n,k) read by rows: fibonomial ratios c(n)/(c(k)*c(n-k)) where c are partial products of a generalized Fibonacci sequence with multiplier m=6.

Original entry on oeis.org

1, 1, 1, 1, 6, 1, 1, 37, 37, 1, 1, 228, 1406, 228, 1, 1, 1405, 53390, 53390, 1405, 1, 1, 8658, 2027415, 12493260, 2027415, 8658, 1, 1, 53353, 76988379, 2923477635, 2923477635, 76988379, 53353, 1, 1, 328776, 2923530988, 684106251192
Offset: 0

Views

Author

Roger L. Bagula, Feb 01 2010

Keywords

Comments

Start from the generalized Fibonacci sequence A005668 and its partial products c(n) = 1, 1, 6, 222, 50616, 71115480, 615717825840, 32850393162041520... Then t(n,k) = c(n)/(c(k)*c(n-k)).
Row sums are 1, 2, 8, 76, 1864, 109592, 16565408, 6001038736, 5589714971584,
12478331908166432, 71624411004755875328,...

Examples

			1;
1, 1;
1, 6, 1;
1, 37, 37, 1;
1, 228, 1406, 228, 1;
1, 1405, 53390, 53390, 1405, 1;
1, 8658, 2027415, 12493260, 2027415, 8658, 1;
1, 53353, 76988379, 2923477635, 2923477635, 76988379, 53353, 1;
1, 328776, 2923530988, 684106251192, 4215654749670, 684106251192, 2923530988, 328776, 1;
		

Crossrefs

Cf. A010048 (m=1), A099927 (m=2), A172342 (m=5), A172345 (m=7).

Programs

  • Mathematica
    Clear[f, c, a, t];
    f[0, a_] := 0; f[1, a_] := 1;
    f[n_, a_] := f[n, a] = a*f[n - 1, a] + f[n - 2, a];
    c[n_, a_] := If[n == 0, 1, Product[f[i, a], {i, 1, n}]];
    t[n_, m_, a_] := c[n, a]/(c[m, a]*c[n - m, a]);
    Table[Table[Table[t[n, m, a], {m, 0, n}], {n, 0, 10}], {a, 1, 10}];
    Table[Flatten[Table[Table[t[n, m, a], {m, 0, n}], {n, 0, 10}]], {a, 1, 10}]
Showing 1-10 of 14 results. Next