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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A213579 Rectangular array: (row n) = b**c, where b(h) = F(h), c(h) = n-1+h, where F=A000045 (Fibonacci numbers), n>=1, h>=1, and ** = convolution.

Original entry on oeis.org

1, 3, 2, 7, 5, 3, 14, 11, 7, 4, 26, 21, 15, 9, 5, 46, 38, 28, 19, 11, 6, 79, 66, 50, 35, 23, 13, 7, 133, 112, 86, 62, 42, 27, 15, 8, 221, 187, 145, 106, 74, 49, 31, 17, 9, 364, 309, 241, 178, 126, 86, 56, 35, 19, 10, 596, 507, 397, 295, 211, 146, 98, 63, 39, 21
Offset: 1

Views

Author

Clark Kimberling, Jun 18 2012

Keywords

Comments

Principal diagonal: A213580.
Antidiagonal sums: A053808.
Row 1, (1,1,2,3,5,...)**(1,2,3,4,...): A001924.
Row 2, (1,1,2,3,5,...)**(2,3,4,5,...): A023548.
Row 3, (1,1,2,3,5,...)**(3,4,5,6,...): A023552.
Row 4, (1,1,2,3,5,...)**(4,5,6,7,...): A210730.
Row 5, (1,1,2,3,5,...)**(5,6,7,8,...): A210731.
For a guide to related arrays, see A213500.

Examples

			Northwest corner (the array is read by falling antidiagonals):
1....3....7....14...26...46
2....5....11...21...38...66
3....7....15...28...50...86
4....9....19...35...62...106
5....11...23...42...74...126
6....13...27...49...86...146
		

Crossrefs

Programs

  • GAP
    Flat(List([1..12], n-> List([1..n], k-> Fibonacci(k+3) + n*Fibonacci(k+2) -(n+k+2) ))); # G. C. Greubel, Jul 08 2019
  • Magma
    [[Fibonacci(k+3) + n*Fibonacci(k+2) -(n+k+2): k in [1..n]]: n in [1..12]]; // G. C. Greubel, Jul 08 2019
    
  • Mathematica
    (* First program *)
    b[n_]:= Fibonacci[n]; c[n_]:= n;
    T[n_, k_]:= Sum[b[k-i] c[n+i], {i, 0, k-1}]
    TableForm[Table[T[n, k], {n, 1, 10}, {k, 1, 10}]]
    Flatten[Table[T[n-k+1, k], {n, 12}, {k, n, 1, -1}]] (* A213579 *)
    r[n_]:= Table[T[n, k], {k, 40}]
    d = Table[T[n, n], {n, 1, 40}] (* A213580 *)
    s[n_]:= Sum[T[i, n+1-i], {i, 1, n}]
    s1 = Table[s[n], {n, 1, 50}] (* A053808 *)
    (* Second program *)
    Table[Fibonacci[n-k+4] +k*Fibonacci[n-k+3] -(n+3), {n, 12}, {k, n}]//Flatten (* G. C. Greubel, Jul 08 2019 *)
  • PARI
    t(n,k) = fibonacci(n-k+4) + k*fibonacci(n-k+3) - (n+3);
    for(n=1,12, for(k=1,n, print1(t(n,k), ", "))) \\ G. C. Greubel, Jul 08 2019
    
  • Sage
    [[fibonacci(k+3) + n*fibonacci(k+2) -(n+k+2) for k in (1..n)] for n in (1..12)] # G. C. Greubel, Jul 08 2019
    

Formula

T(n,k) = 3*T(n,k-1) - 2*T(n,k-2) - T(n,k-3) + T(n,k-4).
G.f. for row n: f(x)/g(x), where f(x) = n - (n-1)*x and g(x) = (1-x-x^2) *(1-x)^2.
T(n, k) = Fibonacci(k+3) + n*Fibonacci(k+2) - (n+k+2). - G. C. Greubel, Jul 08 2019

A033937 Convolution of natural numbers n >= 1 with Fibonacci numbers F(k), k >= 3.

Original entry on oeis.org

2, 7, 17, 35, 66, 118, 204, 345, 575, 949, 1556, 2540, 4134, 6715, 10893, 17655, 28598, 46306, 74960, 121325, 196347, 317737, 514152, 831960, 1346186, 2178223, 3524489, 5702795, 9227370, 14930254, 24157716
Offset: 0

Views

Author

Keywords

Crossrefs

Programs

  • GAP
    List([0..40], n-> Fibonacci(n+7) -3*n-11) # G. C. Greubel, Jul 05 2019
  • Magma
    [Fibonacci(n+7) -3*n-11: n in [0..40]]; // G. C. Greubel, Jul 05 2019
    
  • Mathematica
    Table[Fibonacci[n+7] -3*n-11, {n,0,40}] (* G. C. Greubel, Jul 05 2019 *)
  • PARI
    vector(40, n, n--; fibonacci(n+7) -3*n-11) \\ G. C. Greubel, Jul 05 2019
    
  • Sage
    [fibonacci(n+7) -3*n-11 for n in (0..40)] # G. C. Greubel, Jul 05 2019
    

Formula

a(n) = Fibonacci(n+7) - (11+3*n).
G.f.: (2+x)/((1-x-x^2)*(1-x)^2).

A120297 Sum of all matrix elements of n X n matrix M(i,j) = Fibonacci(i+j-1).

Original entry on oeis.org

1, 5, 20, 65, 193, 544, 1489, 4005, 10660, 28193, 74273, 195200, 512257, 1343077, 3519412, 9219105, 24144289, 63224096, 165544721, 433437125, 1134810436, 2971065025, 7778499265, 20364618240, 53315655553, 139582833989
Offset: 1

Views

Author

Alexander Adamchuk, Jul 11 2006

Keywords

Comments

p^2 divides a(p-1) for p = 5, 11, 19, 29, 31, 41, 59, 61, 71, ... = A038872 (Primes congruent to {0, 1, 4} mod 5), also odd primes p such that where 5 is a square mod p. All squared prime divisors of a(n) also belong to A038872.

Examples

			Matrix begins:
  1  1  2  3  5
  1  2  3  5  8
  2  3  5  8 13
  3  5  8 13 21
  5  8 13 21 34
		

Crossrefs

Programs

  • Mathematica
    Table[Sum[Sum[Fibonacci[i+j-1],{i,1,n}],{j,1,n}],{n,1,50}]

Formula

a(n) = Sum_{j=1..n} Sum_{i=1..n} Fibonacci(i+j-1).
a(n) = Fibonacci(2*n+3) - 2*Fibonacci(n+3) + 2. - Vladeta Jovovic, Jul 21 2006
G.f.: (1 - x^3 + 2*x^2)/((x-1)*(x^2 + x - 1)*(x^2 - 3*x + 1)). - Maksym Voznyy (voznyy(AT)mail.ru), Aug 14 2009

A152687 Partial products operator applied thrice to nonzero Fibonacci numbers.

Original entry on oeis.org

1, 1, 2, 24, 8640, 746496000, 201231433728000000, 3554168771933456302080000000000, 139840535301953855934724122328694784000000000000000, 674129921807822677705190163721626103970522196466131271680000000000000000000000
Offset: 1

Views

Author

Keywords

Comments

Partial products of A152686.

Crossrefs

Programs

  • Mathematica
    Nest[FoldList[Times,#]&,Fibonacci[Range[10]],3] (* Harvey P. Dale, Oct 06 2017 *)
  • PARI
    a(n) = prod(i=1, n, prod(j=1, i, prod(k=1, j, fibonacci(k)))); \\ Michel Marcus, Sep 15 2018

Extensions

Edited by R. J. Mathar, Dec 12 2008
One more term (a(10)) from Harvey P. Dale, Oct 06 2017

A197649 a(n) = Sum_{k=0..n} k*Fibonacci(2*k).

Original entry on oeis.org

0, 1, 7, 31, 115, 390, 1254, 3893, 11789, 35045, 102695, 297516, 853932, 2432041, 6881395, 19361995, 54214939, 151164018, 419910354, 1162585565, 3209268665, 8835468881, 24266461007, 66501634776, 181882282200, 496539007825, 1353272290399, 3682496714743
Offset: 0

Views

Author

Gary Detlefs, Oct 16 2011

Keywords

Comments

There are only a small number of Fibonacci identities that can be solved for n. Some of these are
1. n = (-F(4*n) + 5*Sum_{k=1..n} F(2*k-1)^2)/2 (Vajda #95).
2. n = (F(n+3) - 2 + Sum_{k=0..n} k*F(k))/F(n+2). (A104286)
3. n = (a(n) + F(2*n))/F(2*n+1).
4. n = F(n+4) - 3 - Sum_{k=0..1} (F(k+2) - 1). (A001924)
n can also be expressed in terms of phi = (1+sqrt(5))/2:
5. n = floor(n*phi^3) - floor(2*n*phi).
6. n = (floor(2*n*phi^2) - floor(2*n*phi))/2.

Crossrefs

Cf. A023619 (inverse binomial transform).

Programs

  • Maple
    a:=n->sum(k*fibonacci(2*k),n= 0..n):seq(a(n), n=0..25);
  • Mathematica
    Table[Sum[k*Fibonacci[2*k], {k, 0, n}], {n, 0, 50}] (* T. D. Noe, Oct 17 2011 *)

Formula

a(n) = n*F(2*n+1) - F(2*n), where F(n) = Fibonacci(n).
a(n) = ((F(2*n+1)*((n-1)*h(n-1) - (n-1)*h(n-2)) - h(n)*F(2*n))/h(n), n > 2, where h(n) is the n-th harmonic number.
From R. J. Mathar, Oct 17 2011: (Start)
G.f.: x*(1+x) / (x^2-3*x+1)^2.
a(n) = A001871(n-1) + A001871(n-2). (End)
a(n) ~ c*n*(3 + sqrt(5))^n*2^(-n), where c = (5 + sqrt(5))/10. - Stefano Spezia, Mar 29 2022
E.g.f.: 2*exp(3*x/2)*(5*x*cosh(sqrt(5)*x/2) + sqrt(5)*(2*x - 1)*sinh(sqrt(5)*x/2))/5. - Stefano Spezia, Mar 04 2025

Extensions

Identity 4 added by Gary Detlefs, Dec 22 2012

A202876 Symmetric matrix based on A000071, by antidiagonals.

Original entry on oeis.org

1, 2, 2, 4, 5, 4, 7, 10, 10, 7, 12, 18, 21, 18, 12, 20, 31, 38, 38, 31, 20, 33, 52, 66, 70, 66, 52, 33, 54, 86, 111, 122, 122, 111, 86, 54, 88, 141, 184, 206, 214, 206, 184, 141, 88, 143, 230, 302, 342, 362, 362, 342, 302, 230, 143, 232, 374, 493, 562, 602
Offset: 1

Views

Author

Clark Kimberling, Dec 26 2011

Keywords

Comments

Let s=A000071 (Fibonacci numbers -1), and let T be the infinite square matrix whose n-th row is formed by putting n-1 zeros before the terms of s. Let T' be the transpose of T. Then A202876 represents the matrix product M=T'*T. M is the self-fusion matrix of s, as defined at A193722. See A202877 for characteristic polynomials of principal submatrices of M, with interlacing zeros.

Examples

			Northwest corner:
1....2....4....7....12....20
2....5....10...18...31....52
4....10...21...38...66....111
7....18...38...70...122...206
12...31...66...122..214...362
		

Crossrefs

Programs

  • Mathematica
    s[k_] := -1 + Fibonacci[k + 2];
    U = NestList[Most[Prepend[#, 0]] &, #, Length[#] - 1] &[Table[s[k], {k, 1, 15}]];
    L = Transpose[U]; M = L.U; TableForm[M]
    m[i_, j_] := M[[i]][[j]];
    Flatten[Table[m[i, n + 1 - i], {n, 1, 12}, {i, 1, n}]]
    f[n_] := Sum[m[i, n], {i, 1, n}] + Sum[m[n, j], {j, 1, n - 1}]
    Table[f[n], {n, 1, 12}]
    Table[Sqrt[f[n]], {n, 1, 12}]  (* A001924 *)
    Table[m[1, j], {j, 1, 12}]     (* A000071 *)
    Table[m[j, j], {j, 1, 12}]     (* A202462 *)

A213576 Rectangular array: (row n) = b**c, where b(h) = h, c(h) = F(n-1+h), where F=A000045 (Fibonacci numbers), n >= 1, h >= 1, and ** = convolution.

Original entry on oeis.org

1, 3, 1, 7, 4, 2, 14, 10, 7, 3, 26, 21, 17, 11, 5, 46, 40, 35, 27, 18, 8, 79, 72, 66, 56, 44, 29, 13, 133, 125, 118, 106, 91, 71, 47, 21, 221, 212, 204, 190, 172, 147, 115, 76, 34, 364, 354, 345, 329, 308, 278, 238, 186, 123, 55, 596, 585, 575, 557, 533, 498, 450, 385, 301, 199, 89
Offset: 1

Views

Author

Clark Kimberling, Jun 18 2012

Keywords

Comments

Principal diagonal: A213577.
Antidiagonal sums: A213578.
Row 1, (1,2,3,...)**(1,1,2,3,5,...): A001924;
Row 2, (1,2,3,...)**(1,2,3,5,8,...): A001891;
Row 3, (1,2,3,...)**(2,3,5,8,13,...): A033937;
Row 4, (1,2,3,...)**(3,5,8,13,21,...): A033960;
Row 5, (1,2,3,...)**(5,8,13,21,...): A037140;
Row 6, (1,2,3,...)**(8,13,21,34,...): A037157.
For a guide to related arrays, see A213500.
The falling antidiagonal rows can be computed by the sum Sum_{j=0..n-k} (n-k-j+1)*Fibonacci(k+j) which can also be seen as Fibonacci(n+4) - Lucas(k+2) - (n-k)*Fibonacci(k+1). - G. C. Greubel, Jul 05 2019

Examples

			Northwest corner (the array is read by falling antidiagonals):
  1,   3,   7,  14,  26,  46,  79
  1,   4,  10,  21,  40,  72, 125
  2,   7,  17,  35,  66, 118, 204
  3,  11,  27,  56, 106, 190, 329
  5,  18,  44,  91, 172, 308, 533
  8,  29,  71, 147, 278, 498, 862
		

Crossrefs

Cf. A213500.

Programs

  • GAP
    Flat(List([1..10], n-> List([1..n], k-> Fibonacci(n+4) - (n-k+1) *Fibonacci(k+1) - Fibonacci(k+3)))); # G. C. Greubel, Jul 05 2019
  • Magma
    [[Fibonacci(n+4) -(n-k)*Fibonacci(k+1) -Lucas(k+2): k in [1..n]]: n in [1..10]]; // G. C. Greubel, Jul 05 2019
    
  • Mathematica
    (* First Program *)
    b[n_]:= n; c[n_]:= Fibonacci[n];
    t[n_, k_]:= Sum[b[k-i] c[n+i], {i, 0, k-1}]
    TableForm[Table[t[n, k], {n, 1, 10}, {k, 1, 10}]]
    Flatten[Table[t[n-k+1, k], {n, 12}, {k, n, 1, -1}]] (* A213576 *)
    r[n_]:= Table[t[n, k], {k,1,40}]  (* columns of antidiagonal triangle *)
    d = Table[t[n, n], {n, 1, 40}] (* A213577 *)
    s[n_]:= Sum[t[i, n + 1 - i], {i, 1, n}]
    s1 = Table[s[n], {n, 1, 50}] (* A213578 *)
    (* Second Program *)
    T[n_, k_]:= Fibonacci[n+4] - (n-k)*Fibonacci[k+1] - LucasL[k+2];
    Table[T[n,k], {n,10}, {k,n}]//Flatten (* G. C. Greubel, Jul 05 2019 *)
  • PARI
    T(n, k)= fibonacci(n+4) - (n-k+1)*fibonacci(k+1) - fibonacci(k+3);
    for(n=1,10, for(k=1,n, print1(T(n,k), ", "))) \\ G. C. Greubel, Jul 05 2019
    
  • Sage
    [[fibonacci(n+4) - (n-k+1)*fibonacci(k+1) - fibonacci(k+3) for k in (1..n)] for n in (1..10)] # G. C. Greubel, Jul 05 2019
    

Formula

Rows: T(n,k) = 3*T(n,k-1) - 2*T(n,k-2) - T(n,k-3) + T(n,k-4).
Columns: T(n,k) = T(n-1,k) + T(n-2,k).
G.f. for row n: f(x)/g(x), where f(x) = F(n) - F(n-1)*x and g(x) = (1 - x - x^2)*(1 - x)^2.
T(n,k) = F(n+k+3) - k*F(n+1) - F(n+3). - Ehren Metcalfe, Jul 04 2019

A316939 Triangle read by rows formed using Pascal's rule except that n-th row begins and ends with Fibonacci(n+2).

Original entry on oeis.org

1, 2, 2, 3, 4, 3, 5, 7, 7, 5, 8, 12, 14, 12, 8, 13, 20, 26, 26, 20, 13, 21, 33, 46, 52, 46, 33, 21, 34, 54, 79, 98, 98, 79, 54, 34, 55, 88, 133, 177, 196, 177, 133, 88, 55, 89, 143, 221, 310, 373, 373, 310, 221, 143, 89, 144, 232, 364, 531, 683, 746, 683, 531, 364, 232, 144, 233, 376, 596, 895, 1214, 1429
Offset: 0

Views

Author

Vincenzo Librandi, Jul 28 2018

Keywords

Examples

			Triangle begins:
   1;
   2,  2;
   3,  4,   3;
   5,  7,   7,   5;
   8, 12,  14,  12,   8;
  13, 20,  26,  26,  20,  13;
  21, 33,  46,  52,  46,  33,  21;
  34, 54,  79,  98,  98,  79,  54, 34;
  55, 88, 133, 177, 196, 177, 133, 88, 55;
  ...
		

Crossrefs

Cf. A316528 (row sums).
Columns k=0..2: A000045, A000071, A001924.
Other Fibonacci borders: A074829, A108617, A316938.

Programs

  • Maple
    f:= proc(n,k) option remember;
      if k=0 or k=n then combinat:-fibonacci(n+2) else procname(n-1,k)+procname(n-1,k-1) fi
    end proc:
    for n from 0 to 10 do
      seq(f(n,k),k=0..n)
    od; # Robert Israel, Sep 20 2018
  • Mathematica
    t={}; Do[r={}; Do[If[k==0||k==n, m=Fibonacci[n + 2], m=t[[n, k]] + t[[n, k + 1]]]; r=AppendTo[r, m], {k, 0, n}]; AppendTo[t, r], {n, 0, 10}]; t // Flatten

Extensions

Incorrect g.f. removed by Georg Fischer, Feb 18 2020

A033960 Convolution of natural numbers n >= 1 with Fibonacci numbers F(k), k >= 4.

Original entry on oeis.org

3, 11, 27, 56, 106, 190, 329, 557, 929, 1534, 2516, 4108, 6687, 10863, 17623, 28564, 46270, 74922, 121285, 196305, 317693, 514106, 831912, 1346136, 2178171, 3524435, 5702739, 9227312, 14930194, 24157654, 39088001
Offset: 0

Views

Author

Keywords

Crossrefs

Programs

  • GAP
    List([0..40], n-> Fibonacci(n+8) -5*n-18) # G. C. Greubel, Jul 05 2019
  • Magma
    [Fibonacci(n+8) -5*n-18: n in [0..40]]; // G. C. Greubel, Jul 05 2019
    
  • Mathematica
    Table[Fibonacci[n+8] -5*n-18, {n,0,40}] (* G. C. Greubel, Jul 05 2019 *)
  • PARI
    vector(40, n, n--; fibonacci(n+8) -5*n-18) \\ G. C. Greubel, Jul 05 2019
    
  • Sage
    [fibonacci(n+8) -5*n-18 for n in (0..40)] # G. C. Greubel, Jul 05 2019
    

Formula

a(n) = Fibonacci(n+8) - (18+5*n).
G.F.: (3+2*x)/((1-x-x^2)*(1-x)^2).

A037140 Convolution of natural numbers n >= 1 with Fibonacci numbers F(k), for k >= 5.

Original entry on oeis.org

5, 18, 44, 91, 172, 308, 533, 902, 1504, 2483, 4072, 6648, 10821, 17578, 28516, 46219, 74868, 121228, 196245, 317630, 514040, 831843, 1346064, 2178096, 3524357, 5702658, 9227228, 14930107, 24157564, 39087908, 63245717, 102333878, 165579856, 267914003
Offset: 0

Views

Author

Keywords

Crossrefs

Programs

  • GAP
    List([0..40], n-> Fibonacci(n+9) -8*n-29) # G. C. Greubel, Jul 05 2019
  • Magma
    [Fibonacci(n+9) -8*n-29: n in [0..40]]; // G. C. Greubel, Jul 05 2019
    
  • Mathematica
    Table[Fibonacci[n+9] -8*n-29, {n,0,40}] (* G. C. Greubel, Jul 05 2019 *)
  • PARI
    vector(40, n, n--; fibonacci(n+9) -8*n-29) \\ G. C. Greubel, Jul 05 2019
    
  • Sage
    [fibonacci(n+9) -8*n-29 for n in (0..40)] # G. C. Greubel, Jul 05 2019
    

Formula

a(n) = Fibonacci(n+9) - (29+8*n).
G.f.: (5+3*x)/((1-x-x^2)*(1-x)^2).

Extensions

Corrected by Franklin T. Adams-Watters, Oct 25 2006
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