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 135 results. Next

A073387 Convolution triangle of A002605(n) (generalized (2,2)-Fibonacci), n>=0.

Original entry on oeis.org

1, 2, 1, 6, 4, 1, 16, 16, 6, 1, 44, 56, 30, 8, 1, 120, 188, 128, 48, 10, 1, 328, 608, 504, 240, 70, 12, 1, 896, 1920, 1872, 1080, 400, 96, 14, 1, 2448, 5952, 6672, 4512, 2020, 616, 126, 16, 1, 6688, 18192, 23040, 17856, 9352, 3444, 896, 160, 18, 1
Offset: 0

Views

Author

Wolfdieter Lang, Aug 02 2002

Keywords

Comments

The g.f. for the row polynomials P(n,x) = Sum_{m=0..n} T(n,m)*x^m is 1/(1-(2+x+2*z)*z). See Shapiro et al. reference and comment under A053121 for such convolution triangles.
T(n, k) is the number of words of length n over {0,1,2,3} having k letters 3 and avoiding runs of odd length for the letters 0,1. - Milan Janjic, Jan 14 2017

Examples

			Lower triangular matrix, T(n,k), n >= k >= 0, else 0:
    1;
    2,    1;
    6,    4,    1;
   16,   16,    6,    1;
   44,   56,   30,    8,   1;
  120,  188,  128,   48,  10,   1;
  328,  608,  504,  240,  70,  12,   1;
  896, 1920, 1872, 1080, 400,  96,  14,  1;
		

Crossrefs

Cf. A002605, A007482 (row sums), A053121, A073403, A073404.
Columns: A002605 (k=0), A073388 (k=1), A073389 (k=2), A073390 (k=3), A073391 (k=4), A073392 (k=5), A073393 (k=6), A073394 (k=7), A073397 (k=8), A073398 (k=9).

Programs

  • Magma
    A073387:= func< n,k | (&+[2^(n-k-j)*Binomial(n-j,k)*Binomial(n-k-j,j): j in [0..Floor((n-k)/2)]]) >;
    [A073387(n,k): k in [0..n], n in [0..12]]; // G. C. Greubel, Oct 03 2022
    
  • Maple
    T := (n,k) -> `if`(n=0,1,2^(n-k)*binomial(n,k)*hypergeom([(k-n)/2, (k-n+1)/2], [-n], -2)): seq(seq(simplify(T(n,k)),k=0..n),n=0..10); # Peter Luschny, Apr 25 2016
  • Mathematica
    T[n_, k_]:=T[n,k]=Sum[2^(n-k-j)*Binomial[n-j,k]*Binomial[n-k-j,j], {j,0,(n-k)/2}];
    Table[T[n,k], {n,0,10}, {k,0,n}]//Flatten (* Jean-François Alcover, Jun 04 2019 *)
  • SageMath
    def A073387(n,k): return sum(2^(n-k-j)*binomial(n-j,k)*binomial(n-k-j,j) for j in range(((n-k+2)//2)))
    flatten([[A073387(n,k) for k in range(n+1)] for n in range(12)]) # G. C. Greubel, Oct 03 2022

Formula

T(n, k) = 2*(p(k-1, n-k)*(n-k+1)*T(n-k+1) + q(k-1, n-k)*(n-k+2)*T(n-k))/(k!*12^k), n >= k >= 1, with T(n) = T(n, k=0) = A002605(n), else 0; p(m, n) = Sum_{j=0..m} A(m, j)*n^(m-j) and q(m, n) = Sum_{j=0..m} B(m, j)*n^(m-j) with the number triangles A(k, m) = A073403(k, m) and B(k, m) = A073404(k, m).
T(n, k) = Sum_{j=0..floor((n-k)/2)} 2^(n-k-j)*binomial(n-j, k)*binomial(n-k-j, j) if n > k, else 0.
T(n, k) = ((n-k+1)*T(n, k-1) + 2*(n+k)*T(n-1, k-1))/(6*k), n >= k >= 1, T(n, 0) = A002605(n+1), else 0.
Sum_{k=0..n} T(n, k) = A007482(n).
G.f. for column m (without leading zeros): 1/(1-2*x*(1+x))^(m+1), m>=0.
T(n,k) = 2^(n-k)*binomial(n,k)*hypergeom([(k-n)/2, (k-n+1)/2], [-n], -2) for n>=1. - Peter Luschny, Apr 25 2016
From G. C. Greubel, Oct 03 2022: (Start)
T(n, n-1) = A005843(n), n >= 1.
T(n, n-2) = 2*A005563(n-1), n >= 2.
T(n, n-3) = 4*A159920(n-1), n >= 2.
Sum_{k=0..n} (-1)^k*T(n, k) = A001045(n+1).
Sum_{k=0..floor(n/2)} T(n-k, k) = A015518(n+1). (End)

A073388 Convolution of A002605(n) (generalized (2,2)-Fibonacci), n >= 0, with itself.

Original entry on oeis.org

1, 4, 16, 56, 188, 608, 1920, 5952, 18192, 54976, 164608, 489088, 1443776, 4238336, 12382208, 36022272, 104407296, 301618176, 868765696, 2495715328, 7152286720, 20452548608, 58369409024
Offset: 0

Views

Author

Wolfdieter Lang, Aug 02 2002

Keywords

Crossrefs

Second (m=1) column of triangle A073387.
Cf. A002605.

Programs

  • GAP
    List([0..25], n->2^n*Sum([0..Int(n/2)],k->Binomial(n-k+1,1)*Binomial(n-k,k)*(1/2)^k)); # Muniru A Asiru, Jun 12 2018
    
  • Magma
    R:=PowerSeriesRing(Integers(), 30); Coefficients(R!( 1/(1-2*x-2*x^2)^2 )); // G. C. Greubel, Oct 03 2022
  • Mathematica
    CoefficientList[Series[1/(1-2*x-2*x^2)^2, {x,0,40}], x] (* G. C. Greubel, Oct 03 2022 *)
  • Sage
    taylor( 1/(1-2*x-2*x^2)^2, x, 0, 24).list() # Zerinvary Lajos, Jun 03 2009; modified by G. C. Greubel, Oct 03 2022
    

Formula

a(n) = Sum_{k=0..n} b(k)*b(n-k), with b(k) = A002605(k).
a(n) = Sum_{k=0..floor(n/2)} binomial(n-k+1, 1)*binomial(n-k, k)*2^(n-k).
a(n) = ((n+1)*U(n+1) + 2*(n+2)*U(n))/6, with U(n) = A002605(n), n >= 0.
G.f.: 1/(1-2*x*(1+x))^2.
a(n) = Sum_{k=0..floor((n+2)/2)} k*binomial(n-k+2, k)2^(n-k+1). - Paul Barry, Oct 15 2004

A073389 Second convolution of A002605(n) (generalized (2,2)-Fibonacci), n >= 0, with itself.

Original entry on oeis.org

1, 6, 30, 128, 504, 1872, 6672, 23040, 77616, 256288, 832416, 2666496, 8441600, 26454528, 82174464, 253280256, 775316736, 2358812160, 7137023488, 21487386624, 64401106944, 192229535744, 571630694400, 1693996941312, 5004131659776, 14738997288960, 43293528760320
Offset: 0

Views

Author

Wolfdieter Lang, Aug 02 2002

Keywords

Crossrefs

Third (m=2) column of triangle A073387, A073388.
Cf. A002605.

Programs

  • GAP
    List([0..25], n->2^n*Sum([0..Int(n/2)],k->Binomial(n-k+2,2)*Binomial(n-k,k)*(1/2)^k)); # Muniru A Asiru, Jun 12 2018
    
  • Magma
    R:=PowerSeriesRing(Integers(), 30); Coefficients(R!( 1/(1-2*x-2*x^2)^3 )); // G. C. Greubel, Oct 03 2022
  • Mathematica
    CoefficientList[Series[1/(1-2x(1+x))^3,{x,0,25}],x]  (* Harvey P. Dale, Mar 14 2011 *)
  • Sage
    taylor( 1/(1-2*x-2*x^2)^3, x, 0, 25).list() # Zerinvary Lajos, Jun 03 2009; modified by G. C. Greubel, Oct 03 2022
    

Formula

a(n) = Sum_{k=0..n} b(k)*c(n-k) with b(k) = A002605(k) and c(k) = A073388(k).
a(n) = Sum_{k=0..floor(n/2)} binomial(n-k+2, 2)*binomial(n-k, k)*2^(n-k).
a(n) = (n+3)*((n+1)*U(n+1) + (n+2)*U(n))/12, with U(n) = A002605(n), n >= 0.
G.f.: 1/(1-2*x*(1+x))^3.

A073405 Coefficient triangle of polynomials (rising powers) related to convolutions of A002605(n), n >= 0, (generalized (2,2)-Fibonacci). Companion triangle is A073406.

Original entry on oeis.org

1, 36, 12, 1536, 888, 120, 80448, 62592, 15168, 1152, 5068800, 4813056, 1600704, 222336, 10944, 375598080, 413351424, 169917696, 32811264, 2992896, 103680, 32103751680, 39661608960, 19066503168, 4592982528
Offset: 0

Views

Author

Wolfdieter Lang, Aug 02 2002

Keywords

Comments

The row polynomials are p(k,x) := sum(a(k,m)*x^m,m=0..k), k=0,1,2,...
The k-th convolution of U0(n) := A002605(n), n >= 0, ((2,2) Fibonacci numbers starting with U0(0)=1) with itself is Uk(n) := A073387(n+k,k) = 2*(p(k-1,n)*(n+1)*U0(n+1) + q(k-1,n)*(n+2)*U0(n))/(k!*12^k)), k=1,2,..., where the companion polynomials q(k,n) := sum(b(k,m)*n^m,m=0..k), k >= 0, are the row polynomials of triangle b(k,m)= A073406(k,m).

Examples

			k=2: U2(n)=2*((36+12*n)*(n+1)*U0(n+1)+(36+12*n)*(n+2)*U0(n))/(2!*12^2), cf. A073389.
Triangle begins:
  1;
  36, 12;
  1536, 888, 120;
  ... (lower triangular matrix a(k,m), k >= m >= 0, else 0).
		

Crossrefs

Formula

Recursion for row polynomials defined in the comments: p(k, n)= 2*(2*(n+2)*p(k-1, n+1)+2*(n+2*(k+1))*p(k-1, n)+(n+3)*q(k-1, n+1)); q(k, n)= 4*((n+1)*p(k-1, n+1)+(n+2*(k+1))*q(k-1, n)), k >= 1. [Corrected by Sean A. Irvine, Nov 25 2024]

A073403 Coefficient triangle of polynomials (falling powers) related to convolutions of A002605(n), n>=0, (generalized (2,2)-Fibonacci). Companion triangle is A073404.

Original entry on oeis.org

1, 12, 36, 120, 888, 1536, 1152, 15168, 62592, 80448, 10944, 222336, 1600704, 4813056, 5068800, 103680, 2992896, 32811264, 169917696, 413351424, 375598080, 981504, 38112768, 587976192, 4592982528
Offset: 0

Views

Author

Wolfdieter Lang, Aug 02 2002

Keywords

Comments

The row polynomials are p(k,x) := sum(a(k,m)*x^(k-m),m=0..k), k=0,1,2,..
The k-th convolution of U0(n) := A002605(n), n>= 0, ((2,2) Fibonacci numbers starting with U0(0)=1) with itself is Uk(n) := A073387(n+k,k) = 2*(p(k-1,n)*(n+1)*U0(n+1) + q(k-1,n)*(n+2)*U0(n))/(k!*12^k), k=1,2,..., where the companion polynomials q(k,n) := sum(b(k,m)*n^(k-m),m=0..k) are the row polynomials of triangle b(k,m)= A073404(k,m).

Examples

			k=2: U2(n)=(2*(36+12*n)*(n+1)*U0(n+1)+2*(36+12*n)*(n+2)*U0(n))/(2!*12^2), cf. A073389.
1; 12,36; 120,888,1536; ... (lower triangular matrix a(k,m), k >= m >= 0, else 0).
		

Crossrefs

Formula

Recursion for row polynomials defined in the comments: see A073405.

A073390 Third convolution of A002605(n) (generalized (2,2)-Fibonacci), n >= 0, with itself.

Original entry on oeis.org

1, 8, 48, 240, 1080, 4512, 17856, 67776, 248880, 889600, 3109376, 10664448, 35989248, 119761920, 393676800, 1280157696, 4122985728, 13165099008, 41713192960, 131243970560, 410315433984, 1275348344832
Offset: 0

Views

Author

Wolfdieter Lang, Aug 02 2002

Keywords

Crossrefs

Fourth (m=3) column of triangle A073387.

Programs

  • GAP
    List([0..25], n->2^n*Sum([0..Int(n/2)],k->Binomial(n-k+3,3)*Binomial(n-k,k)*(1/2)^k)); # Muniru A Asiru, Jun 12 2018
    
  • Magma
    R:=PowerSeriesRing(Integers(), 40); Coefficients(R!( 1/(1-2*x-2*x^2)^4 )); // G. C. Greubel, Oct 03 2022
    
  • Mathematica
    CoefficientList[Series[1/(1-2*x-2*x^2)^4, {x,0,40}], x] (* G. C. Greubel, Oct 03 2022 *)
  • SageMath
    def A073390_list(prec):
        P. = PowerSeriesRing(ZZ, prec)
        return P( 1/(1-2*x-2*x^2)^4 ).list()
    A073390_list(40) # G. C. Greubel, Oct 03 2022

Formula

a(n) = Sum_{k=0..n} b(k)*c(n-k) with b(k) = A002605(k) and c(k) = A073389(k).
a(n) = Sum_{k=0..floor(n/2)} binomial(n-k+3, 3)*binomial(n-k, k)*2^(n-k).
a(n) = ((64 + 37*n + 5*n^2)*(n+1)*U(n+1) + 4*(11 + 7*n + n^2)*(n+2)*U(n))/(6^3), with U(n) = A002605(n), n >= 0.
G.f.: 1/(1-2*x*(1+x))^4.

A073391 Fourth convolution of A002605(n) (generalized (2,2)-Fibonacci), n >= 0, with itself.

Original entry on oeis.org

1, 10, 70, 400, 2020, 9352, 40600, 167680, 665440, 2555840, 9551936, 34880000, 124853120, 439228160, 1521839360, 5202292736, 17571249920, 58712184320, 194280061440, 637228462080, 2073332481024, 6696470231040
Offset: 0

Views

Author

Wolfdieter Lang, Aug 02 2002

Keywords

Crossrefs

Fifth (m=4) column of triangle A073387.

Programs

  • GAP
    List([0..25], n->2^n*Sum([0..Int(n/2)],k->Binomial(n-k+4,4)*Binomial(n-k,k)*(1/2)^k)); # Muniru A Asiru, Jun 12 2018
    
  • Magma
    R:=PowerSeriesRing(Integers(), 40); Coefficients(R!( 1/(1-2*x-2*x^2)^5 )); // G. C. Greubel, Oct 04 2022
    
  • Mathematica
    CoefficientList[Series[1/(1-2*x-2*x^2)^5, {x,0,40}], x] (* G. C. Greubel, Oct 04 2022 *)
  • SageMath
    def A073391_list(prec):
        P. = PowerSeriesRing(ZZ, prec)
        return P( 1/(1-2*x-2*x^2)^5 ).list()
    A073391_list(40) # G. C. Greubel, Oct 04 2022

Formula

a(n) = Sum_{k=0..n} b(k)*c(n-k), with b(k) = A002605(k) and c(k) = A073390(k).
a(n) = Sum_{k=0..floor(n/2)} binomial(n-k+4, 4)*binomial(n-k, k)*2^(n-k).
a(n) = (2*(419 + 326*n + 79*n^2 + 6*n^3)*(n+1)*U(n+1) + (458 + 421*n + 112*n^2 + 9*n^3)*(n+2)*U(n))/(2^5*3^4), with U(n) = A002605(n), n >= 0.
G.f.: 1/(1-2*x*(1+x))^5.

A073392 Fifth convolution of A002605(n) (generalized (2,2)-Fibonacci), n >= 0, with itself.

Original entry on oeis.org

1, 12, 96, 616, 3444, 17472, 82432, 367488, 1565280, 6421376, 25525248, 98773248, 373450112, 1383674880, 5036089344, 18041821184, 63727070976, 222249968640, 766234140672, 2614196680704, 8834194123776
Offset: 0

Views

Author

Wolfdieter Lang, Aug 02 2002

Keywords

Examples

			x^6 + 12*x^7 + 96*x^8 + 616*x^9 + 3444*x^10 + ... + 222249968640*x^23 + 766234140672*x^24 + 2614196680704*x^25 + 8834194123776*x^26 + ... - _Zerinvary Lajos_, Jun 03 2009
		

Crossrefs

Sixth (m=5) column of triangle A073387.

Programs

  • GAP
    List([0..30], n->2^n*Sum([0..Int(n/2)],k->Binomial(n-k+5,5)*Binomial(n-k,k)*(1/2)^k)); # Muniru A Asiru, Jun 12 2018
    
  • Magma
    R:=PowerSeriesRing(Integers(), 40); Coefficients(R!( 1/(1-2*x-2*x^2)^6 )); // G. C. Greubel, Oct 04 2022
  • Mathematica
    CoefficientList[Series[1/(1-2*x*(1+x))^6, {x,0,30}],x] (* Harvey P. Dale, May 12 2018 *)
  • Sage
    taylor( 1/(1-2*x-2*x^2)^6, x, 0, 30).list() # Zerinvary Lajos, Jun 03 2009; modified by G. C. Greubel, Oct 04 2022
    

Formula

a(n) = Sum_{k=0..n} b(k)*c(n-k), with b(k) = A002605(k) and c(k) = A073391(k).
a(n) = Sum_{k=0..floor(n/2)} binomial(n-k+5, 5)*binomial(n-k, k)*2^(n-k).
a(n) = (n+4)*(n+8)*((19*n^2 + 158*n + 275)*(n+1)*U(n+1) + 2*(7*n^2 + 52*n + 65)*(n+2)*U(n))/(2^6*3^4*5), with U(n) = A002605(n), n >= 0.
G.f.: 1/(1-2*x*(1+x))^6.

A073393 Sixth convolution of A002605(n) (generalized (2,2)-Fibonacci), n >= 0, with itself.

Original entry on oeis.org

1, 14, 126, 896, 5488, 30240, 153888, 735744, 3344544, 14581952, 61378240, 250693632, 997593856, 3880249856, 14791776768, 55385874432, 204082373376, 741186464256, 2656771815936, 9410113241088
Offset: 0

Views

Author

Wolfdieter Lang, Aug 02 2002

Keywords

Examples

			x^7 + 14*x^8 + 126*x^9 + 896*x^10 + 5488*x^11 + ... + 204082373376*x^23 + 741186464256*x^24 + 2656771815936*x^25 + 9410113241088*x^26 + ... - _Zerinvary Lajos_, Jun 03 2009
		

Crossrefs

Seventh (m=6) column of triangle A073387.

Programs

  • Magma
    R:=PowerSeriesRing(Rationals(), 40); Coefficients(R!( 1/(1-2*x-2*x^2)^7 )); // G. C. Greubel, Oct 05 2022
  • Mathematica
    CoefficientList[Series[1/(1-2x(1+x))^7,{x,0,30}],x] (* or *)
    LinearRecurrence[{14,-70,112,196,-728,-168,1920,336,-2912,-1568,1792,2240,896,128},{1,14,126,896,5488,30240,153888,735744,3344544,14581952,61378240,250693632, 997593856,3880249856},30](* Harvey P. Dale, Jan 24 2013 *)
  • SageMath
    taylor( 1/(1-2*x-2*x^2)^7, x, 0, 26).list() # Zerinvary Lajos, Jun 03 2009; modified by G. C. Greubel, Oct 05 2022
    

Formula

a(n) = Sum_{k=0..n} b(k)*c(n-k) with b(k) = A002605(k) and c(k) = A073392(k).
a(n) = Sum_{k=0..floor(n/2)} binomial(n-k+6, 6)*binomial(n-k, k)*2^(n-k).
a(n) = ((54340 + 59802*n + 24583*n^2 + 4747*n^3 + 433*n^4 + 15*n^5)*(n+1)*U(n+1) + (23420 + 32768*n + 15333*n^2 + 3201*n^3 + 307*n^4 + 11*n^5)*(n+2)*U(n))/(2^7*3^5*5), with U(n) := A002605(n), n >= 0.
G.f.: 1/(1-2*x*(1+x))^7.
a(0)=1, a(1)=14, a(2)=126, a(3)=896, a(4)=5488, a(5)=30240, a(6)=153888, a(7)=735744, a(8)=3344544, a(9)=14581952, a(10)=61378240, a(11)=250693632, a(12)=997593856, a(13)=3880249856, a(n) = 14*a(n-1) - 70*a(n-2) + 112*a(n-3) + 196*a(n-4) - 728*a(n-5) - 168*a(n-6) + 1920*a(n-7) + 336*a(n-8) - 2912*a(n-9) - 1568*a(n-10) + 1792*a(n-11) + 2240*a(n-12) + 896*a(n-13) + 128*a(n-14). - Harvey P. Dale, Jan 24 2013

A073394 Seventh convolution of A002605(n) (generalized (2,2)-Fibonacci), n >= 0, with itself.

Original entry on oeis.org

1, 16, 160, 1248, 8304, 49344, 269184, 1372800, 6628512, 30584576, 135804416, 583471616, 2436145920, 9919484928, 39503038464, 154230921216, 591550292736, 2232748892160, 8305370185728, 30486351396864, 110551407403008, 396424924397568, 1406924861276160, 4945692873129984, 17231635316293632
Offset: 0

Views

Author

Wolfdieter Lang, Aug 02 2002

Keywords

Examples

			G.f. = 1 + 16*x + 160*x^2 + 1248*x^3 + ... + 154230921216*x^15 + 591550292736*x^16 + 2232748892160*x^17 + 8305370185728*x^18 + ... - _Zerinvary Lajos_, Jun 03 2009
		

Crossrefs

Eighth (m=7) column of triangle A073387.

Programs

  • Magma
    R:=PowerSeriesRing(Integers(), 30); Coefficients(R!( 1/(1-2*x-2*x^2)^8 )); // G. C. Greubel, Oct 06 2022
  • Mathematica
    CoefficientList[Series[1/(1-2*x-2*x^2)^8, {x,0,30}], x] (* G. C. Greubel, Oct 06 2022 *)
    LinearRecurrence[{16,-96,224,112,-1344,896,3712,-3168,-7424,3584,10752,1792,-7168,-6144,-2048,-256},{1,16,160,1248,8304,49344,269184,1372800,6628512,30584576,135804416,583471616,2436145920,9919484928,39503038464,154230921216},30] (* Harvey P. Dale, Nov 21 2023 *)
  • SageMath
    taylor( 1/(1-2*x-2*x^2)^8, x, 0, 26).list() # Zerinvary Lajos, Jun 03 2009; modified by G. C. Greubel, Oct 06 2022
    

Formula

a(n) = Sum_{k=0..n} b(k)*c(n-k) with b(k) = A002605(k) and c(k) = A073393(k).
a(n) = Sum_{k=0..floor(n/2)} binomial(n-k+7, 7)*binomial(n-k, k)*2^(n-k).
a(n) = ((2322320 + 2869040*n + 1379232*n^2 + 332247*n^3 + 42533*n^4 + 2757*n^5 + 71*n^6)*(n+1)*U(n+1) + 4*(235900 + 375554*n + 207009*n^2 + 54174*n^3 + 7318*n^4 + 492*n^5 + 13*n^6)*(n+2)*U(n))/(2^8*3^6*5*7), with U(n) = A002605(n), n >= 0.
G.f.: 1/(1-2*x*(1+x))^8.

Extensions

Terms a(19) onward added by G. C. Greubel, Oct 06 2022
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