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 46 results. Next

A128380 A097806^24 * A000594.

Original entry on oeis.org

1, 0, -48, -24, 1104, 1128, -15892, -25368, 156240, 360640, -1057908, -3600696, 4417678, 26438568, -3155508, -144207816, -112109568, 564538680, 1002957320, -1344487080, -5096138658, -111333800, 17182425012, 17552839368, -34668142443, -86942440944, 4993723500, 236551774320
Offset: 1

Views

Author

Gary W. Adamson, Feb 28 2007

Keywords

Comments

Conjecture: Given the infinite set of sequences generated from the pairwise operation on A000594 (A097806^k * A000594), k = 24, (A128380) is the only sequence in the set with a zero. The sequence generated from k=23 = (1, -1, -47, 23, 1081, 47, -15939, ...). Analogous conjecture with the partial sum operator: (Cf. A128378, A128379); in which zeros are conjectured to occur only with k=23 and k=24. A128380 mod 24 = 1, 0, 0, 0, 0, 0, -4, 0, 0, 16, ...

Crossrefs

Programs

  • Mathematica
    Nest[Prepend[Most[#] + Rest[#], First[#]] &, RamanujanTau[Range[30]], 24] (* Amiram Eldar, Jan 08 2025 *)

Formula

Pairwise operation performed 24 times on A000594

Extensions

More terms from Amiram Eldar, Jan 08 2025

A128540 Triangle A127647 * A097806, read by rows.

Original entry on oeis.org

1, 1, 1, 0, 2, 2, 0, 0, 3, 3, 0, 0, 0, 5, 5, 0, 0, 0, 0, 8, 8, 0, 0, 0, 0, 0, 13, 13, 0, 0, 0, 0, 0, 0, 21, 21, 0, 0, 0, 0, 0, 0, 0, 34, 34, 0, 0, 0, 0, 0, 0, 0, 0, 55, 55, 0, 0, 0, 0, 0, 0, 0, 0, 0, 89, 89, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 144, 144
Offset: 1

Views

Author

Gary W. Adamson, Mar 10 2007

Keywords

Comments

Row sums = A094895 starting (1, 2, 4, 6, 10, 16, 26, ...). A128541 = A097806 * A127647.

Examples

			First few rows of the triangle:
  1;
  1, 1;
  0, 2, 2;
  0, 0, 3, 3;
  0, 0, 0, 5, 5;
  0, 0, 0, 0, 8, 8;
  ...
		

Crossrefs

Programs

  • Magma
    [k eq n select Fibonacci(n) else k eq n-1 select Fibonacci(n) else 0: k in [1..n], n in [1..15]]; // G. C. Greubel, Jul 11 2019
    
  • Mathematica
    Table[If[k==n || k==n-1, Fibonacci[n], 0], {n, 15}, {k, n}]//Flatten (* G. C. Greubel, Jul 11 2019 *)
  • PARI
    T(n,k) = if(k==n || k==n-1, fibonacci(n), 0); \\ G. C. Greubel, Jul 11 2019
    
  • Sage
    def T(n, k):
        if (k==n): return fibonacci(n)
        elif (k==n-1): return fibonacci(n)
        else: return 0
    [[T(n, k) for k in (1..n)] for n in (1..15)] # G. C. Greubel, Jul 11 2019

Formula

A127646 * A097806 as infinite lower triangular matrices.

A131108 T(n,k) = 2*A007318(n,k) - A097806(n,k).

Original entry on oeis.org

1, 1, 1, 2, 3, 1, 2, 6, 5, 1, 2, 8, 12, 7, 1, 2, 10, 20, 20, 9, 1, 2, 12, 30, 40, 30, 11, 1, 2, 14, 42, 70, 70, 42, 13, 1, 2, 16, 56, 112, 140, 112, 56, 15, 1, 2, 18, 72, 168, 252, 252, 168, 72, 17, 1, 2, 20, 90, 240, 420, 504, 420, 240, 90, 19, 1
Offset: 0

Views

Author

Gary W. Adamson, Jun 15 2007

Keywords

Comments

Row sums give A095121.
Triangle T(n,k), 0 <= k <= n, read by rows given by [1, 1, -2, 1, 0, 0, 0, 0, 0, 0, 0, ...] DELTA [1,0,0,1,0,0,0,0,0,0,0,...] where DELTA is the operator defined in A084938. - Philippe Deléham, Dec 18 2007

Examples

			First few rows of the triangle are:
  1;
  1,  1;
  2,  3,  1;
  2,  6,  5,  1;
  2,  8, 12,  7, 1;
  2, 10, 20, 20, 9, 1;
...
		

Crossrefs

Programs

  • Magma
    function T(n,k)
      if k eq n-1 then return 2*n-1;
      elif k eq n then return 1;
      else return 2*Binomial(n,k);
      end if;
      return T;
    end function;
    [T(n,k): k in [0..n], n in [0..12]]; // G. C. Greubel, Nov 18 2019
    
  • Maple
    seq(seq( `if`(k=n-1, 2*n-1, `if`(k=n, 1, 2*binomial(n,k))), k=0..n), n=0..12); # G. C. Greubel, Nov 18 2019
  • Mathematica
    Table[If[k==n-1, 2*n-1, If[k==n, 1, 2*Binomial[n, k]]], {n,0,12}, {k,0, n}]//Flatten (* G. C. Greubel, Nov 18 2019 *)
  • PARI
    T(n,k) = if(k==n-1, 2*n-1, if(k==n, 1, 2*binomial(n,k))); \\ G. C. Greubel, Nov 18 2019
    
  • Sage
    @CachedFunction
    def T(n, k):
        if (k==n-1): return 2*n-1
        elif (k==n): return 1
        else: return 2*binomial(n,k)
    [[T(n, k) for k in (0..n)] for n in (0..12)] # G. C. Greubel, Nov 18 2019

Formula

Twice Pascal's triangle minus A097806, the pairwise operator.
G.f.: (1-x*y+x^2+x^2*y)/((-1+x+x*y)*(x*y-1)). - R. J. Mathar, Aug 11 2015

Extensions

Corrected by Philippe Deléham, Dec 17 2007
More terms added and data corrected by G. C. Greubel, Nov 18 2019

A128541 Triangle, A097806 * A127647, read by rows.

Original entry on oeis.org

1, 1, 1, 0, 1, 2, 0, 0, 2, 3, 0, 0, 0, 3, 5, 0, 0, 0, 0, 5, 8, 0, 0, 0, 0, 0, 8, 13, 0, 0, 0, 0, 0, 0, 13, 21, 0, 0, 0, 0, 0, 0, 0, 21, 34, 0, 0, 0, 0, 0, 0, 0, 0, 34, 55, 0, 0, 0, 0, 0, 0, 0, 0, 0, 55, 89, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 89, 144, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 144, 233
Offset: 0

Views

Author

Gary W. Adamson, Mar 10 2007

Keywords

Comments

Row sums = A000045 starting (1, 2, 3, 5, 8, 13, ...). A128540 = A127647 * A097806.

Examples

			First few rows of the triangle:
  1;
  1, 1;
  0, 1, 2;
  0, 0, 2, 3;
  0, 0, 0, 3, 5;
  0, 0, 0, 0, 5, 8;
  ...
		

Crossrefs

Programs

  • Magma
    [k eq n select Fibonacci(n+1) else k eq n-1 select Fibonacci(n) else 0: k in [0..n], n in [0..15]]; // G. C. Greubel, Jul 11 2019
    
  • Mathematica
    Table[If[k==n, Fibonacci[n+1], If[k==n-1, Fibonacci[n], 0]], {n, 0, 15}, {k, 0, n}]//Flatten (* G. C. Greubel, Jul 11 2019 *)
  • PARI
    T(n,k) = if(k==n, fibonacci(n+1), if(k==n-1, fibonacci(n), 0)); \\ G. C. Greubel, Jul 11 2019
    
  • Sage
    def T(n, k):
        if (k==n): return fibonacci(n+1)
        elif (k==n-1): return fibonacci(n)
        else: return 0
    [[T(n, k) for k in (0..n)] for n in (0..15)] # G. C. Greubel, Jul 11 2019

Formula

A097806 * A127647 as infinite lower triangular matrices.

Extensions

More terms added by G. C. Greubel, Jul 11 2019

A129573 A097806 * A129372.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 0, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1
Offset: 1

Views

Author

Gary W. Adamson, Apr 22 2007

Keywords

Examples

			First few rows of the triangle are:
  1;
  1, 1;
  1, 1, 1;
  1, 0, 1, 1;
  1, 0, 0, 1, 1;
  1, 1, 0, 0, 1, 1;
  1, 1, 0, 0, 0, 1, 1;
  1, 0, 0, 0, 0, 0, 1, 1;
  ...
		

Crossrefs

Row sums are A129574.

Programs

  • PARI
    T(n,k)=(n%k==0 && n/k%2) || ((n-1)%k==0 && (n-1)/k%2) \\ Andrew Howroyd, Aug 10 2018

Formula

A097806 * A129372 as infinite lower triangular matrices.

Extensions

Duplicate a(35) removed and terms a(56) and beyond from Andrew Howroyd, Aug 10 2018

A131033 A130296 * A097806.

Original entry on oeis.org

1, 3, 1, 4, 2, 1, 5, 2, 2, 1, 6, 2, 2, 2, 1, 7, 2, 2, 2, 2, 1, 8, 2, 2, 2, 2, 2, 1, 9, 2, 2, 2, 2, 2, 2, 1, 10, 2, 2, 2, 2, 2, 2, 2, 1, 11, 2, 2, 2, 2, 2, 2, 2, 2, 1, 12, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 13, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 14, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1
Offset: 1

Views

Author

Gary W. Adamson, Jun 10 2007

Keywords

Comments

Row sums give A016777.
A131032 = A097806 * A130296. [corrected by Georg Fischer, Oct 10 2021]

Examples

			First few rows of the triangle are:
1;
3, 1;
4, 2, 1;
5, 2, 2, 1;
6, 2, 2, 2, 1;
7, 2, 2, 2, 2, 1;
...
		

Crossrefs

Formula

A130296 * A097806 as infinite lower triangular matrices; where A130296 = (1; 2,1; 3,1,1;...) and A097806 = the pairwise operator.

Extensions

Definition corrected, a(36)=2 inserted and more terms from Georg Fischer, Oct 10 2021
More terms from Michel Marcus, Oct 11 2021

A133599 A097806 * A133080 * A007318.

Original entry on oeis.org

1, 3, 1, 3, 3, 1, 3, 7, 5, 1, 3, 9, 10, 5, 1, 3, 13, 22, 18, 7, 1, 3, 15, 31, 34, 21, 7, 1, 3, 19, 51, 75, 65, 33, 9, 1, 3, 21, 64, 111, 120, 83, 36, 9, 1, 3, 25, 92, 196, 266, 238, 140, 52, 11, 1
Offset: 1

Views

Author

Gary W. Adamson, Sep 18 2007

Keywords

Comments

Row sums = A133600: (1, 4, 7, 16, 28, 64, 112, ...).

Examples

			First few rows of the triangle:
  1;
  3,  1;
  3,  3,  1;
  3,  7,  5,  1;
  3,  9, 10,  5,  1;
  3, 13, 22, 18,  7,  1;
  ...
		

Crossrefs

Programs

Formula

A097806 * A133080 * A007318 as infinite lower triangular matrices, where A097806 = the pairwise operator and A133080 = an interpolation operator.

A134315 A134309 * A097806.

Original entry on oeis.org

1, 1, 1, 0, 2, 2, 0, 0, 4, 4, 0, 0, 0, 8, 8, 0, 0, 0, 0, 16, 16, 0, 0, 0, 0, 0, 32, 32, 0, 0, 0, 0, 0, 0, 64, 64
Offset: 1

Views

Author

Gary W. Adamson, Oct 19 2007

Keywords

Comments

A134315 * [1,2,3,...] = A128135: (1, 3, 10 28, 72, 176, 416, ...).
Triangle read by rows given by [1,-1,0,0,0,0,0,0,...] DELTA [1,1,0,0,0,0,0,0,0,...] where DELTA is the operator defined in A084938. - Philippe Deléham, Oct 20 2007

Examples

			First few rows of the triangle are:
  1;
  1, 1;
  0, 2, 2;
  0, 0, 4, 4;
  0, 0, 0, 8, 8;
  ...
		

Crossrefs

Formula

A134309 * A134315 as infinite lower triangular matrices. Triangle read by rows, for n>1, (n-1) zeros followed by 2^(n-1), 2^(n-1). As an infinite lower triangular matrix, (1, 1, 2, 4, 8, ...) in the main diagonal and (1, 2, 4, 8, ...) in the subdiagonal.
G.f.: (-1-x+x*y)/(-1+2*x*y). - R. J. Mathar, Aug 11 2015

A129479 Triangle read by rows: A054523 * A097806 as infinite lower triangular matrices.

Original entry on oeis.org

1, 2, 1, 2, 1, 1, 3, 1, 1, 1, 4, 0, 0, 1, 1, 4, 3, 1, 0, 1, 1, 6, 0, 0, 0, 0, 1, 1, 6, 2, 1, 1, 0, 0, 1, 1, 6, 2, 2, 0, 0, 0, 0, 1, 1, 8, 4, 0, 1, 1, 0, 0, 0, 1, 1, 10, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 6, 4, 4, 2, 1, 1, 0, 0, 0, 0, 1, 1, 12, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1
Offset: 1

Views

Author

Gary W. Adamson, Apr 17 2007

Keywords

Examples

			First few rows of the triangle:
  1;
  2, 1;
  2, 1, 1;
  3, 1, 1, 1;
  4, 0, 0, 1, 1;
  4, 3, 1, 0, 1, 1;
  6, 0, 0, 0, 0, 1, 1;
  6, 2, 1, 1, 0, 0, 1, 1;
  ...
		

Crossrefs

Cf. A000010 (alternating row sums), A053158 (row sums).

Programs

  • Magma
    A054523:= func< n,k | n eq 1 select 1 else (n mod k) eq 0 select EulerPhi(Floor(n/k)) else 0 >;
    A129479:= func< n,k | k le n-1 select A054523(n,k) + A054523(n,k+1) else 1 >;
    [A129479(n,k): k in [1..n], n in [1..16]]; // G. C. Greubel, Feb 11 2024
    
  • Mathematica
    A054523[n_, k_]:= If[n==1, 1, If[Divisible[n,k], EulerPhi[n/k], 0]];
    T[n_, k_]:= If[kA054523[n, j+k], {j,0,1}], 1];
    Table[T[n,k],{n,16},{k,n}]//Flatten (* G. C. Greubel, Feb 11 2024 *)
  • SageMath
    def A054523(n,k):
        if (k==n): return 1
        elif (n%k): return 0
        else: return euler_phi(n//k)
    def A129479(n, k):
        if k<0 or k>n: return 0
        elif k==n: return 1
        else: return A054523(n,k) + A054523(n,k+1)
    flatten([[A129479(n, k) for k in range(1,n+1)] for n in range(1,17)]) # G. C. Greubel, Feb 11 2024

Formula

Sum_{k=1..n} T(n, k) = A053158(n) (row sums).
T(n, 1) = A126246(n).
From G. C. Greubel, Feb 11 2024: (Start)
T(n, k) = A054523(n, k) + A054523(n, k+1) for k < n, otherwise 1.
T(2*n-1, n) = A019590(n).
T(2*n, n) = A054977(n).
T(2*n+1, n) = A000038(n).
T(3*n, n) = A063524(n-1).
T(3*n-2, n) = A183918(n+2).
Sum_{k=1..n} (-1)^(k-1) * T(n, k) = A000010(n). (End)

A130452 Triangle read by rows: A097806 * A130321 as infinite lower triangular matrices.

Original entry on oeis.org

1, 3, 1, 6, 3, 1, 12, 6, 3, 1, 24, 12, 6, 3, 1, 48, 24, 12, 6, 3, 1, 96, 48, 24, 12, 6, 3, 1, 192, 96, 48, 24, 12, 6, 3, 1, 384, 192, 96, 48, 24, 12, 6, 3, 1, 768, 384, 192, 96, 48, 24, 12, 6, 3, 1, 1536, 768, 384, 192, 96, 48, 24, 12, 6, 3, 1, 3072, 1536, 768, 384, 192, 96, 48, 24, 12, 6, 3, 1
Offset: 1

Views

Author

Gary W. Adamson, May 26 2007

Keywords

Comments

Row sums = A033484: (1, 4, 10, 22, 46, 94, 190, ...).

Examples

			First few rows of the triangle:
   1;
   3,  1;
   6,  3,  1;
  12,  6,  3,  1;
  24, 12,  6,  3,  1;
  48, 24, 12,  6,  3,  1;
  ...
		

Crossrefs

Formula

A097806 * A130321 as infinite lower triangular matrices. A097806 = the pairwise operator, A130321 = [1; 2,1; 4,2,1; ...]. Triangle, A003945 (1, 3, 6, 12, 24, 48, ...) in every column.

Extensions

a(28) = 1 inserted and more terms from Georg Fischer, May 29 2023
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