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 12 results. Next

A067418 Triangle A067330 with rows read backwards.

Original entry on oeis.org

1, 2, 1, 5, 3, 2, 10, 7, 5, 3, 20, 15, 12, 8, 5, 38, 30, 25, 19, 13, 8, 71, 58, 50, 40, 31, 21, 13, 130, 109, 96, 80, 65, 50, 34, 21, 235, 201, 180, 154, 130, 105, 81, 55, 34, 420, 365, 331, 289, 250, 210, 170, 131, 89, 55, 744, 655, 600, 532, 469, 404, 340, 275, 212, 144, 89, 1308, 1164, 1075, 965
Offset: 0

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Author

Wolfdieter Lang, Feb 15 2002

Keywords

Comments

The column m (without leading 0's) gives the convolution of Fibonacci numbers F(n+1) := A000045(n+1), n>=0, with those with m-shifted index: a(n+m,m)=sum(F(k+1)*F(m+n+1-k),k=0..n), n>=0, m=0,1,...
The row polynomials p(n,x) := sum(a(n,m)*x^m,m=0..n) are generated by A(z)*(A(z)-x*A(x*z))/(1-x), with A(x) := 1/(1-x-x^2) (g.f. for Fibonacci F(n+1), n>=0).
The columns give A001629(n+2), A023610, A067331-4, A067430-1, A067977-8 for m= 0..9, respectively. Row sums give A067988.

Examples

			{1}; {2,1}; {5,3,2}; {10,7,5,3}; ...; p(2,n)=5+3*x+2*x^2.
		

Programs

  • Mathematica
    Reverse /@ Table[Sum[Fibonacci[k + 1] Fibonacci[n - k + 1], {k, 0, m}], {n, 0, 11}, {m, 0, n}] // Flatten (* Michael De Vlieger, Apr 11 2016 *)

Formula

a(n, m)=A067330(n, n-m), n>=m>=0, else 0.
a(n, m)= (((3*(n-m)+5)*F(n-m+1)+(n-m+1)*F(n-m))*F(m+1)+((n-m)*F(n-m+1)+2*(n-m+1)*F(n-m))*F(m))/5.
G.f. for column m=0, 1, ...: (x^m)*(F(m+1)+F(m)*x)/(1-x-x^2)^2, with F(m) := A000045(m) (Fibonacci).
a(n, m) = ((-1)^m*F(n-2*m+1)-m*L(n+2)+n*L(n+2)+5*F(n)+4*F(n-1))/5, with F(-n) = (-1)^(n+1)*F(n), hence a(n, m) = (2*(n-m+1)*L(n+2)-A067990(n, m))/5, n>=m>=0. - Ehren Metcalfe, Apr 11 2016

A067988 Row sums of triangle A067330; also of triangle A067418.

Original entry on oeis.org

1, 3, 10, 25, 60, 133, 284, 585, 1175, 2310, 4464, 8502, 15995, 29775, 54920, 100487, 182556, 329555, 591550, 1056405, 1877821, 3323868, 5860800, 10297500, 18033925, 31487643, 54824854, 95211205, 164948700, 285121105, 491804144, 846631137, 1454746355, 2495275650
Offset: 0

Views

Author

Wolfdieter Lang, Feb 15 2002

Keywords

Comments

a(n) is the sum of the positions of the 0's in all Fibonacci binary words of length n+1. A Fibonacci binary word is a binary word having no 00 subword. Example: a(3)=25 because the Fibonacci binary words of length 4 are 1110, 1111, 1101, 1010, 1011, 0110, 0111 and 0101, the positions of the 0's being 4, 3, 2, 4, 2, 1, 4, 1, 1 and 3 (their sum is 25). - Emeric Deutsch, Jan 04 2009

Crossrefs

Programs

  • Maple
    a:=n->sum(binomial(n-j,j)*n*j/2,j=0..n): seq(a(n), n=2..30); # Zerinvary Lajos, Oct 19 2006
  • Mathematica
    Table[((n+2)((3n+5)Fibonacci[n+1]+(n+1)Fibonacci[n]))/10,{n,0,30}] (* Harvey P. Dale, Feb 02 2020 *)

Formula

a(n) = (n+2)*((3*n+5)*F(n+1)+(n+1)*F(n))/10, with F(n) := A000045(n) (Fibonacci).
G.f.: (1+x^2)/(1-x-x^2)^3.
Sum_{j=0..n} binomial(n-j,j)*n*j/2. - Zerinvary Lajos, Oct 19 2006
E.g.f.: exp(x/2)*(5*(10 + 18*x + 7*x^2)*cosh(sqrt(5)*x/2) + sqrt(5)*(14 + 46*x + 15*x^2)*sinh(sqrt(5)*x/2))/50. - Stefano Spezia, Aug 30 2025

Extensions

a(29)-a(33) from Stefano Spezia, Aug 30 2025

A067331 Convolution of Fibonacci F(n+1), n >= 0, with F(n+3), n >= 0.

Original entry on oeis.org

2, 5, 12, 25, 50, 96, 180, 331, 600, 1075, 1908, 3360, 5878, 10225, 17700, 30509, 52390, 89664, 153000, 260375, 442032, 748775, 1265832, 2136000, 3598250, 6052061, 10164540, 17048641, 28559450, 47786400, 79870428, 133359715, 222457608, 370747675, 617363100
Offset: 0

Views

Author

Wolfdieter Lang, Feb 15 2002

Keywords

Comments

Third diagonal of A067330. Third column of A067418.
From Emeric Deutsch, Jun 15 2010: (Start)
a(n) is the external path length of the Fibonacci tree of order n+3. A Fibonacci tree of order n (n >= 2) is a complete binary tree whose left subtree is the Fibonacci tree of order n-1 and whose right subtree is the Fibonacci tree of order n-2; each of the Fibonacci trees of order 0 and 1 is defined as a single node. The external path length of a tree is the sum of the levels of its external nodes (i.e., leaves).
a(n) = Sum_{k>=0} k*A178524(n+2,k).
(End)
a(n) equals the penultimate immanant of the (n+3) X (n+3) tridiagonal matrix with ones along the main diagonal, the superdiagonal, and the subdiagonal. - John M. Campbell, Jan 01 2016
a(n) is the sum of the eccentricities of the vertices of the Fibonacci cube G(n+1). Example: a(1)=5; indeed, the Fibonacci cube G(2) is the path graph P(3), the vertices of which have eccentricities 2, 1, 2. - Emeric Deutsch, May 28 2017

Examples

			From _John M. Campbell_, Jan 03 2016: (Start)
Letting n=2, the external path length of the Fibonacci tree T(5) of order n+3=5 illustrated below is 12 = a(2) = F(1)*F(5) + F(2)*F(4) + F(3)*F(3).
     .
    / \
   /\ /\
  /\
(End)
		

References

  • D. E. Knuth, The Art of Computer Programming, Vol. 3, 2nd edition, Addison-Wesley, Reading, MA, 1998, p. 417.

Crossrefs

Programs

  • Magma
    [((7*n+10)*Fibonacci(n+1)+4*(n+1)*Fibonacci(n))/5: n in [0..40]]; // Vincenzo Librandi, Jan 02 2016
    
  • Maple
    f:= gfun:-rectoproc({a(n) = 2*a(n-1)+a(n-2) - 2*a(n-3)-a(n-4),a(0)=2,a(1)=5,a(2)=12,a(3)=25},a(n),remember):
    map(f, [$0..50]); # Robert Israel, Jan 06 2016
  • Mathematica
    LinearRecurrence[{2, 1, -2, -1}, {2, 5, 12, 25}, 70] (* Vincenzo Librandi, Jan 02 2016 *)
    Table[SeriesCoefficient[(2 + x)/(1 - x - x^2)^2, {x, 0, n}], {n, 0, 34}] (* Michael De Vlieger, Jan 02 2016 *)
    Print[Table[Sum[Binomial[n + 3 - i, i]*(n + 2 - 2*i), {i, 0, Floor[(n + 3)/2]}], {n, 0, 100}]] (* John M. Campbell, Jan 04 2016 *)
    Module[{nn=40,fibs},fibs=Fibonacci[Range[nn]];Table[ListConvolve[Take[ fibs,n],Take[fibs,{2,n+2}]],{n,nn-2}]][[All,2]] (* Harvey P. Dale, Aug 03 2019 *)
  • PARI
    Vec((2+x)/(1-x-x^2)^2 + O(x^100)) \\ Altug Alkan, Jan 04 2016

Formula

a(n) = A067330(n+2, n) = A067418(n+2, 2) = Sum_{k=0..n} F(k+1)*F(n+3-k), n >= 0.
a(n) = ((7*n + 10)*F(n + 1) + 4*(n + 1)*F(n))/5, with F(n) = A000045(n) (Fibonacci).
G.f.: (2 + x)/(1 - x - x^2)^2.
a(n) = Sum_{i=0..floor((n+3)/2)} binomial(n+3-i, i)*(n + 2 - 2*i). - John M. Campbell, Jan 04 2016
E.g.f.: exp(x/2)*((50 + 55*x)*cosh(sqrt(5)*x/2) + sqrt(5)*(18 + 25*x)*sinh(sqrt(5)*x/2))/25. - Stefano Spezia, Dec 04 2023

A067979 Triangle read by rows of incomplete convolutions of Lucas numbers L(n+1) = A000204(n+1), n>=0.

Original entry on oeis.org

1, 3, 6, 4, 13, 17, 7, 19, 31, 38, 11, 32, 48, 69, 80, 18, 51, 79, 107, 140, 158, 29, 83, 127, 176, 220, 274, 303, 47, 134, 206, 283, 360, 432, 519, 566, 76, 217, 333, 459, 580, 706, 822, 963, 1039, 123, 351, 539, 742, 940, 1138, 1341, 1529, 1757, 1880, 199, 568, 872, 1201, 1520, 1844, 2163, 2492, 2796, 3165, 3364
Offset: 0

Views

Author

Wolfdieter Lang, Feb 15 2002

Keywords

Comments

The diagonals d>=0 (d=0: main diagonal) give convolutions of Lucas numbers L(n+1) := A000204(n+1), n>=0, with those with d-shifted index: a(d+n,d) = Sum_{k=0..n} L(k+1)*L(d+n+1-k).
The diagonals give A004799(n-1), A067980-7 for d=n-m= 0..8, respectively. Row sums give A067989.
The row polynomials p(n,x) := sum(a(n,m)*x^m,m=0..n) are generated by A(x*z)*(A(z)-x*A(x*z))/(1-x), with A(x) := (1+2*x)/(1-x-x^2) (g.f. Lucas L(n+1), n>=0).

Examples

			Triangle begins:
  {1};
  {3,6};
  {4,13,17};     p(2,x) = 4+13*x+17*x^2
  {7,19,31,38};
  ...
		

Crossrefs

Cf. A067990 (triangle with rows read backwards).

Programs

  • Mathematica
    Table[Sum[LucasL[k + 1] LucasL[n - k + 1], {k, 0, m}], {n, 0, 10}, {m, 0, n}] // Flatten (* Michael De Vlieger, Apr 11 2016 *)
  • PARI
    for(n=0,10, for(k=0,n, print1(sum(m=0,k,(fibonacci(m+2) + fibonacci(m))*(fibonacci(n-m+2) + fibonacci(n-m))), ", "))) \\ G. C. Greubel, Dec 17 2017

Formula

a(n, m) = Sum_{k=0..m} L(k+1)*L(n-k+1), n>=m>=0, else 0.
a(n, m) = (m+1)*L(n-m+1)*F(m) + ((m+1)*L(n-m+1) + m*L(n-m))*F(m+1), n>=m>=0, with F(n) := A000045(n) (Fibonacci) and L(n) := A000032(n) (Lucas).
G.f. for diagonals d= n-m>=0: (x^d)*(L(d+1)+L(d)*x)*(1-2*x)/(1-x-x^2)^2.
a(n, m) = -(-1)^m*F(n-2*m-1) + m*L(n+2)+F(n+3), with F(-n) = (-1)^(n+1) * F(n), hence a(n, m) = -5*A067330(n, m)+2*(m+1)*L(n+2), n>=m>=0. - Ehren Metcalfe, Apr 11 2016

A067990 Triangle A067979 with rows read backwards.

Original entry on oeis.org

1, 6, 3, 17, 13, 4, 38, 31, 19, 7, 80, 69, 48, 32, 11, 158, 140, 107, 79, 51, 18, 303, 274, 220, 176, 127, 83, 29, 566, 519, 432, 360, 283, 206, 134, 47, 1039, 963, 822, 706, 580, 459, 333, 217, 76, 1880, 1757, 1529, 1341, 1138, 940, 742, 539, 351, 123, 3364, 3165, 2796, 2492, 2163, 1844, 1520, 1201
Offset: 0

Views

Author

Wolfdieter Lang, Feb 15 2002

Keywords

Comments

The column m (without leading 0's) gives the convolution of Lucas numbers {L(n+1) := A000204(n+1)}, n>=0, with those with m-shifted index: a(n+m,m)=sum(L(k+1)*L(m+n+1-k),k=0..n), n>=0,m=0,1,...
The columns give A004799(n-1), A067980-7 for m= 0..8, respectively. Row sums give A067989.
The row polynomials p(n,x) := sum(a(n,m)*x^m,m=0..n) are generated by A(z)*(A(z)-x*A(x*z))/(1-x), with A(x) := (1+2*x)/(1-x-x^2) (g.f. for Lucas {L(n+1)}).

Examples

			{1}; {6,3}; {17,13,4}; {38,31,19,7}; ...; p(2,x)=17+13*x+4*x^2.
		

Programs

  • Mathematica
    Reverse /@ Table[Sum[LucasL[k + 1] LucasL[n - k + 1], {k, 0, m}], {n, 0, 11}, {m, 0, n}] // Flatten (* Michael De Vlieger, Apr 11 2016 *)

Formula

a(n, m)=A067330(n, n-m), n>=m>=0, else 0.
a(n, m)=(n-m+1)*L(m+1)*F(n-m)+((n-m+1)*L(m+1)+(n-m)*L(m))*F(n-m+1), n>=m>=0, else 0; with F(n) := A000045(n)(Fibonacci) and L(n) := A000032(n) (Lucas).
G.f. for column m=0, 1, ...: (x^m)*(L(m+1)+L(m)*x)*(1+2*x)/(1-x-x^2)^2.
a(n, m) = -(-1)^m*F(n-2*m+1)-m*L(n+2)+n*L(n+2)+F(n+3), with F(-n) = (-1)^(n+1)*F(n), hence a(n, m) = -5*A067418(n, m)+2*(n-m+1)*L(n+2), n>=m>=0. - Ehren Metcalfe, Apr 11 2016

A067430 Convolution of Fibonacci F(n+1), n>=0, with F(n+7), n>=0.

Original entry on oeis.org

13, 34, 81, 170, 340, 654, 1227, 2258, 4095, 7340, 13032, 22956, 40169, 69890, 121005, 208606, 358268, 613242, 1046535, 1781170, 3024123, 5123104, 8661456, 14616600, 24624325, 41419234, 69568137, 116690258
Offset: 0

Views

Author

Wolfdieter Lang, Feb 15 2002

Keywords

Crossrefs

Seventh diagonal of A067330. Seventh column of A067418.

Formula

a(n)= A067330(n+6, n) = A067418(n+6, 6)= sum(F(k+1)*F(n+7-k), k=0..n), n>=0.
a(n)= ((47*n+65)*F(n+1)+29*(n+1)*F(n))/5, F(n) := A000045(n) (Fibonacci).
G.f.: (13+8*x)/(1-x-x^2)^2.

A067977 Convolution of Fibonacci F(n+1), n>=0, with F(n+9), n>=0.

Original entry on oeis.org

34, 89, 212, 445, 890, 1712, 3212, 5911, 10720, 19215, 34116, 60096, 105158, 182965, 316780, 546113, 937918, 1605424, 2739760, 4662995, 7916984, 13412019, 22675272, 38265600, 64465450, 108433937
Offset: 0

Views

Author

Wolfdieter Lang, Feb 15 2002

Keywords

Comments

Ninth diagonal of A067330. Ninth column of A067418.

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[(34 + 21*x)/(1 - x - x^2)^2, {x, 0, 30}], x] (* Wesley Ivan Hurt, Feb 16 2017 *)
    LinearRecurrence[{2,1,-2,-1},{34,89,212,445},30] (* Harvey P. Dale, Dec 22 2022 *)

Formula

a(n) = A067330(n+8, n) = A067418(n+8, 8) = Sum_{k=0..n} F(k+1)*F(n+9-k), n>=0.
G.f.: (34+21*x)/(1-x-x^2)^2.
a(n) = ((123*n+5*34)*F(n+1)+76*(n+1)*F(n))/5, F(n) := A000045(n) (Fibonacci); 34=F(9), 76=L(9), 123=L(10), L(n) := A000204(n) (Lucas).

A067332 Convolution of Fibonacci F(n+1), n>=0, with F(n+4), n>=0.

Original entry on oeis.org

3, 8, 19, 40, 80, 154, 289, 532, 965, 1730, 3072, 5412, 9471, 16480, 28535, 49196, 84496, 144638, 246845, 420140, 713353, 1208518, 2043264, 3448200, 5809275, 9771704, 16413019, 27530992, 46122320
Offset: 0

Views

Author

Wolfdieter Lang, Feb 15 2002

Keywords

Comments

Fourth diagonal of A067330. Fourth column of A067418.

Programs

  • Mathematica
    Table[((11n+15)Fibonacci[n+1]+7(n+1)Fibonacci[n])/5,{n,0,30}] (* or *) LinearRecurrence[{2,1,-2,-1},{3,8,19,40},30] (* Harvey P. Dale, Aug 25 2014 *)

Formula

a(n)= A067330(n+3, n) = A067418(n+3, 3) = sum(F(k+1)*F(n+4-k), k=0..n), n>=0.
a(n)= ((11*n+15)*F(n+1)+7*(n+1)*F(n))/5, with F(n) := A000045(n) (Fibonacci).
G.f.: (3+2*x)/(1-x-x^2)^2.
a(0)=3, a(1)=8, a(2)=19, a(3)=40, a(n)=2*a(n-1)+a(n-2)-2*a(n-3)-a(n-4). - Harvey P. Dale, Aug 25 2014

A067333 Convolution of Fibonacci F(n+1), n>=0, with F(n+5), n>=0.

Original entry on oeis.org

5, 13, 31, 65, 130, 250, 469, 863, 1565, 2805, 4980, 8772, 15349, 26705, 46235, 79705, 136886, 234302, 399845, 680515, 1155385, 1957293, 3309096, 5584200, 9407525, 15823765, 26577559, 44579633, 74681770
Offset: 0

Views

Author

Wolfdieter Lang, Feb 15 2002

Keywords

Comments

Fifth diagonal of A067330. Fifth column of A067418.

Formula

a(n)= A067330(n+4, n) = A067418(n+4, 4) = sum(F(k+1)*F(n+5-k), k=0..n), n>=0.
a(n)= ((18*n+25)*F(n+1)+11*(n+1)*F(n))/5, with F(n) := A000045(n) (Fibonacci).
G.f.: (5+3*x)/(1-x-x^2)^2.

A067334 Convolution of Fibonacci F(n+1), n>=0, with F(n+6), n>=0.

Original entry on oeis.org

8, 21, 50, 105, 210, 404, 758, 1395, 2530, 4535, 8052, 14184, 24820, 43185, 74770, 128901, 221382, 378940, 646690, 1100655, 1868738, 3165811, 5352360, 9032400, 15216800, 25595469, 42990578, 72110625, 120804090, 202142180, 337876622, 564176619, 941141410
Offset: 0

Views

Author

Wolfdieter Lang, Feb 15 2002

Keywords

Comments

Sixth diagonal of A067330. Sixth column of A067418.

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[(8+5x)/(1-x-x^2)^2,{x,0,40}],x] (* or *) LinearRecurrence[{2,1,-2,-1},{8,21,50,105},40] (* Harvey P. Dale, Apr 07 2012 *)

Formula

a(n) = A067330(n+5, n) = A067418(n+5, 5) = Sum_{k=0..n} F(k+1)*F(n+6-k), n>=0.
a(n) = ((29*n+40)*F(n+1)+18*(n+1)*F(n))/5, with F(n) := A000045(n) (Fibonacci).
G.f.: (8+5*x)/(1-x-x^2)^2.
a(0)=8, a(1)=21, a(2)=50, a(3)=105, a(n) = 2*a(n-1)+a(n-2)-2*a(n-3)-a(n-4). - Harvey P. Dale, Apr 07 2012

Extensions

More terms from Jason Yuen, Aug 27 2025
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