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 1-3 of 3 results.

A109128 Triangle read by rows: T(n,k) = T(n-1,k-1) + T(n-1,k) + 1 for 0

Original entry on oeis.org

1, 1, 1, 1, 3, 1, 1, 5, 5, 1, 1, 7, 11, 7, 1, 1, 9, 19, 19, 9, 1, 1, 11, 29, 39, 29, 11, 1, 1, 13, 41, 69, 69, 41, 13, 1, 1, 15, 55, 111, 139, 111, 55, 15, 1, 1, 17, 71, 167, 251, 251, 167, 71, 17, 1, 1, 19, 89, 239, 419, 503, 419, 239, 89, 19, 1, 1, 21, 109, 329, 659, 923, 923, 659, 329, 109, 21, 1
Offset: 0

Views

Author

Reinhard Zumkeller, Jun 20 2005

Keywords

Comments

Eigensequence of the triangle = A001861. - Gary W. Adamson, Apr 17 2009

Examples

			Triangle begins as:
  1;
  1   1;
  1   3   1;
  1   5   5   1;
  1   7  11   7   1;
  1   9  19  19   9   1;
  1  11  29  39  29  11   1;
  1  13  41  69  69  41  13   1;
  1  15  55 111 139 111  55  15   1;
  1  17  71 167 251 251 167  71  17   1;
  1  19  89 239 419 503 419 239  89  19   1;
		

Crossrefs

Cf. A000325 (row sums).
Sequence m*binomial(n,k) - (m-1): A007318 (m=1), this sequence (m=2), A131060 (m=3), A131061 (m=4), A131063 (m=5), A131065 (m=6), A131067 (m=7), A168625 (m=8).

Programs

  • Haskell
    a109128 n k = a109128_tabl !! n !! k
    a109128_row n = a109128_tabl !! n
    a109128_tabl = iterate (\row -> zipWith (+)
       ([0] ++ row) (1 : (map (+ 1) $ tail row) ++ [0])) [1]
    -- Reinhard Zumkeller, Apr 10 2012
    
  • Magma
    [2*Binomial(n,k) -1: k in [0..n], n in [0..12]]; // G. C. Greubel, Mar 12 2020
    
  • Maple
    A109128 := proc(n,k)
        2*binomial(n,k)-1 ;
    end proc: # R. J. Mathar, Jul 12 2016
  • Mathematica
    Table[2*Binomial[n,k] -1, {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Mar 12 2020 *)
  • Sage
    [[2*binomial(n,k) -1 for k in (0..n)] for n in (0..12)] # G. C. Greubel, Mar 12 2020

Formula

T(n,k) = T(n-1,k-1) + T(n-1,k) + 1 with T(n,0) = T(n,n) = 1.
Sum_{k=0..n} T(n, k) = A000325(n+1) (row sums).
T(n, k) = 2*binomial(n,k) - 1. - David W. Cantrell (DWCantrell(AT)sigmaxi.net), Sep 30 2007
T(n, 1) = 2*n - 1 = A005408(n+1) for n>0.
T(n, 2) = n^2 + n - 1 = A028387(n-2) for n>1.
T(n, k) = Sum_{j=0..n-k} C(n-k,j)*C(k,j)*(2 - 0^j) for k <= n. - Paul Barry, Apr 27 2006
T(n,k) = A014473(n,k) + A007318(n,k), 0 <= k <= n. - Reinhard Zumkeller, Apr 10 2012
From G. C. Greubel, Apr 06 2024: (Start)
T(n, n-k) = T(n, k).
T(2*n, n) = A134760(n).
T(2*n-1, n) = A030662(n), for n >= 1.
Sum_{k=0..n-1} T(n, k) = A000295(n+1), for n >= 1.
Sum_{k=0..n} (-1)^k*T(n, k) = 2*[n=0] - A000035(n+1).
Sum_{k=0..n-1} (-1)^k*T(n, k) = A327767(n), for n >= 1.
Sum_{k=0..floor(n/2)} T(n-k, k) = A281362(n).
Sum_{k=0..floor((n-1)/2)} T(n-k, k) = A281362(n-1) - (1+(-1)^n)/2 for n >= 1.
Sum_{k=0..floor(n/2)} (-1)^k*T(n-k, k) = b(n), where b(n) is the repeating pattern {1,1,0,-2,-3,-1,2,2,-1,-3,-2,0} with b(n) = b(n-12). (End)

Extensions

Offset corrected by Reinhard Zumkeller, Apr 10 2012

A176203 Triangle read by rows: T(n, k) = 16*binomial(n, k) - 15.

Original entry on oeis.org

1, 1, 1, 1, 17, 1, 1, 33, 33, 1, 1, 49, 81, 49, 1, 1, 65, 145, 145, 65, 1, 1, 81, 225, 305, 225, 81, 1, 1, 97, 321, 545, 545, 321, 97, 1, 1, 113, 433, 881, 1105, 881, 433, 113, 1, 1, 129, 561, 1329, 2001, 2001, 1329, 561, 129, 1, 1, 145, 705, 1905, 3345, 4017, 3345, 1905, 705, 145, 1
Offset: 0

Views

Author

Roger L. Bagula, Apr 11 2010

Keywords

Comments

This sequence belongs to the class defined by T(n, m, q) = 2*T(n, m, q-1) - 1. The first few q values gives the sequences: A007318 (q=0), A109128 (q=1), A131061 (q=2), A168625 (q=3), this sequence (q=4).
Row sums are: {1, 2, 19, 68, 181, 422, 919, 1928, 3961, 8042, 16219, ...}.
Former title: A recursive symmetrical triangular sequence:q=4: t(n, m, q) = 2*t(n, m, q-1) - 1. - G. C. Greubel, Mar 12 2020

Examples

			Triangle begins as:
  1;
  1,   1;
  1,  17,   1;
  1,  33,  33,    1;
  1,  49,  81,   49,    1;
  1,  65, 145,  145,   65,    1;
  1,  81, 225,  305,  225,   81,    1;
  1,  97, 321,  545,  545,  321,   97,    1;
  1, 113, 433,  881, 1105,  881,  433,  113,   1;
  1, 129, 561, 1329, 2001, 2001, 1329,  561, 129,   1;
  1, 145, 705, 1905, 3345, 4017, 3345, 1905, 705, 145, 1;
		

Crossrefs

Sequence m*binomial(n,k) - (m-1): A007318 (m=1), this sequence (m=2), A131060 (m=3), A131061 (m=4), A131063 (m=5), A131065 (m=6), A131067 (m=7), A168625 (m=8), this sequence (m=16).

Programs

  • Magma
    [16*Binomial(n, k) -15: k in [0..n], n in [0..12]]; // G. C. Greubel, Mar 12 2020
    
  • Maple
    A176203:= (n,k) -> 16*binomial(n, k) -15; seq(seq(A176203(n, k), k = 0..n), n = 0.. 12); # G. C. Greubel, Mar 12 2020
  • Mathematica
    T[n_, m_, q]:= 2^q*(Binomial[n, m] -1) + 1; Table[T[n,m,4], {n,0,12}, {m,0,n} ]//Flatten (* modified by G. C. Greubel, Mar 12 2020 *)
    Table[16*Binomial[n, k] -15, {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Mar 12 2020 *)
  • Sage
    [[16*binomial(n, k) -15 for k in (0..n)] for n in (0..12)] # G. C. Greubel, Mar 12 2020

Formula

T(n, m, q) = 2*T(n, m, q-1) - 1, with T(n, m, 0) = binomial(n, m) and q = 4.
From G. C. Greubel, Mar 12 2020: (Start)
T(n, k, q) = 2^q * binomial(n, k) - (2^q - 1), with q = 4.
Sum_{k=0..n} T(n, k, q) = 2^(n + q) - (n + 1)*(2^q - 1) (row sums). (End)

Extensions

Edited by G. C. Greubel, Mar 12 2020

A176204 Triangle T(n, k) = 4 * A008292(n+1, k) - 3, read by rows.

Original entry on oeis.org

1, 1, 1, 1, 13, 1, 1, 41, 41, 1, 1, 101, 261, 101, 1, 1, 225, 1205, 1205, 225, 1, 1, 477, 4761, 9661, 4761, 477, 1, 1, 985, 17169, 62473, 62473, 17169, 985, 1, 1, 2005, 58429, 352933, 624757, 352933, 58429, 2005, 1, 1, 4049, 191357, 1820765, 5241413, 5241413, 1820765, 191357, 4049, 1
Offset: 0

Views

Author

Roger L. Bagula, Apr 11 2010

Keywords

Comments

This sequence belongs to the class defined by T(n, m, q) = 2*T(n, m, q-1) - 1. The first few q values gives the sequences: A008292(n+1, k) (q=0), A176200 (q=1), this sequence (q=2).
Row sums are: {1, 2, 15, 84, 465, 2862, 20139, 161256, 1451493, 14515170, 159667167, ...}.
Former title: A recursive symmetrical triangular sequence based on Eulerian numbers: q=2: T(n, m, q) = 2*T(n, m, q-1) - 1.

Examples

			Triangle begins as:
  1;
  1,    1;
  1,   13,      1;
  1,   41,     41,       1;
  1,  101,    261,     101,       1;
  1,  225,   1205,    1205,     225,       1;
  1,  477,   4761,    9661,    4761,     477,       1;
  1,  985,  17169,   62473,   62473,   17169,     985,      1;
  1, 2005,  58429,  352933,  624757,  352933,   58429,   2005,    1;
  1, 4049, 191357, 1820765, 5241413, 5241413, 1820765, 191357, 4049, 1;
		

Crossrefs

Programs

  • Magma
    Eulerian:= func< n,k | (&+[(-1)^j*Binomial(n+1,j)*(k-j+1)^n: j in [0..k+1]]) >;
    [[4*Eulerian(n+1,k) -3: k in [0..n]]: n in [0..12]]; // G. C. Greubel, Mar 12 2020
    
  • Maple
    A008292:= (n,k) -> add((-1)^j*binomial(n+1,j)*(k-j+1)^n, j=0..k+1);
    A176204:= (n,k,q) -> 2^q*( A008292(n+1,k) -1) + 1;
    seq(seq( A176204(n,k,2), k=0..n), n=0..12); # G. C. Greubel, Mar 12 2020
  • Mathematica
    Eulerian[n_, k_]:= Sum[(-1)^j*Binomial[n+1, j]*(k-j+1)^n, {j,0,k+1}];
    T[n_, m_, q_]:= 2^q*Eulerian[n+1, m] - 2^q +1;
    Table[T[n, m, 2], {n,0,12}, {m,0,n}]//Flatten (* modified by G. C. Greubel, Mar 12 2020 *)
  • PARI
    Eulerian(n,k) = sum(j=0,k+1, (-1)^j*binomial(n+1,j)*(k-j+1)^n);
    T(n,k,q) = 2^q*Eulerian(n+1,k) - (2^q - 1); \\ G. C. Greubel, Mar 12 2020
    
  • Sage
    def Eulerian(n,k): return sum((-1)^j*binomial(n+1,j)*(k-j+1)^n for j in (0..k+1))
    def T(n,k,q): return 2^q*Eulerian(n+1,k) - 2^q + 1
    [[T(n,k,2) for k in (0..n)] for n in (0..12)] # G. C. Greubel, Mar 12 2020

Formula

T(n, m, q) = 2*T(n, m, q-1) - 1, with T(n, m, 0) = A008292(n+1, m).
From G. C. Greubel, Mar 12 2020: (Start)
T(n, k, q) = 2^q * A008292(n+1, k) - (2^q - 1).
Sum_{k=0..n} T(n, k, q) = (n+1)*( 2^q * n! - 2^q + 1) (row sums). (End)

Extensions

Edited by G. C. Greubel, Mar 12 2020
Showing 1-3 of 3 results.