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.

Previous Showing 11-16 of 16 results.

A342891 Triangle read by rows: T(n,k) = generalized binomial coefficients (n,k)_12 (n >= 0, 0 <= k <= n).

Original entry on oeis.org

1, 1, 1, 1, 13, 1, 1, 91, 91, 1, 1, 455, 3185, 455, 1, 1, 1820, 63700, 63700, 1820, 1, 1, 6188, 866320, 4331600, 866320, 6188, 1, 1, 18564, 8836464, 176729280, 176729280, 8836464, 18564, 1, 1, 50388, 71954064, 4892876352, 19571505408, 4892876352, 71954064, 50388, 1
Offset: 0

Views

Author

N. J. A. Sloane, Apr 01 2021

Keywords

Comments

For references, links, programs, etc., see earlier sequences in this series, especially A342889.

Examples

			Triangle begins:
  [1],
  [1, 1],
  [1, 13, 1],
  [1, 91, 91, 1],
  [1, 455, 3185, 455, 1],
  [1, 1820, 63700, 63700, 1820, 1],
  [1, 6188, 866320, 4331600, 866320, 6188, 1],
  [1, 18564, 8836464, 176729280, 176729280, 8836464, 18564, 1],
...
		

Crossrefs

Triangles of generalized binomial coefficients (n,k)_m (or generalized Pascal triangles) for m = 1,...,12: A007318 (Pascal), A001263, A056939, A056940, A056941, A142465, A142467, A142468, A174109, A342889, A342890, A342891.

Programs

  • PARI
    f(n, k, m) = prod(j=1, k, binomial(n-j+m, m)/binomial(j-1+m, m));
    T(n, k) = f(n, k, 12); \\ Seiichi Manyama, Apr 02 2021

Formula

The generalized binomial coefficient (n,k)m = Product{j=1..k} binomial(n+m-j,m)/binomial(j+m-1,m).

A005362 Hoggatt sequence with parameter d=4.

Original entry on oeis.org

1, 2, 7, 32, 177, 1122, 7898, 60398, 494078, 4274228, 38763298, 366039104, 3579512809, 36091415154, 373853631974, 3966563630394, 42997859838010, 475191259977060, 5344193918791710, 61066078557804360, 707984385321707910, 8318207051955884772, 98936727936728464152
Offset: 0

Views

Author

Keywords

Comments

Let V be the vector representation of SL(4) (of dimension 4) and let E be the exterior algebra of V (of dimension 16). Then a(n) is the dimension of the subspace of invariant tensors in the n-th tensor power of E. - Bruce Westbury, Feb 18 2021
This is the number of 4-vicious walkers (aka vicious 4-watermelons) - see Essam and Guttmann (1995). This is the 4-walker analog of A001181. - N. J. A. Sloane, Mar 22 2021

References

  • D. C. Fielder and C. O. Alford, "An investigation of sequences derived from Hoggatt sums and Hoggatt triangles", in G. E. Bergum et al., editors, Applications of Fibonacci Numbers: Proc. Third Internat. Conf. on Fibonacci Numbers and Their Applications, Pisa, Jul 25-29, 1988. Kluwer, Dordrecht, Vol. 3, 1990, pp. 77-88.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Programs

  • Magma
    A056940:= func< n,k | (&*[Binomial(n+j,k)/Binomial(k+j,k): j in [0..3]]) >;
    A005362:= func< n | (&+[A056940(n,k): k in [0..n]]) >;
    [A005362(n): n in [0..30]]; // G. C. Greubel, Nov 14 2022
    
  • Maple
    a := n -> hypergeom([-3-n, -2-n, -1-n, -n], [2, 3, 4], 1):
    seq(simplify(a(n)), n=0..25); # Peter Luschny, Feb 18 2021
  • Mathematica
    A005362[n_]:=HypergeometricPFQ[{-3-n,-2-n,-1-n,-n},{2,3,4},1] (* Richard L. Ollerton, Sep 12 2006 *)
  • SageMath
    def A005362(n): return simplify(hypergeometric([-3-n, -2-n, -1-n, -n],[2,3,4], 1))
    [A005362(n) for n in range(41)] # G. C. Greubel, Nov 14 2022

Formula

From Richard L. Ollerton, Sep 12 2006: (Start)
a(n) = Hypergeometric4F3([-3-n, -2-n, -1-n, -n], [2, 3, 4], 1).
(n+3)*(n+4)*(n+5)*(n+6)*a(n) = 6*(n+1)*(n+3)*(n+4)*(2*n+5)*a(n-1) + 4*(n-1)*n*(4*n+7)*(4*n+9)*a(n-2); a(0)=1, a(1)=2. (End)
a(n) = S(4,n) where S(d,n) is defined in A005364. - Sean A. Irvine, May 29 2016
a(n) ~ 3 * 2^(4*n + 29/2) / (Pi^(3/2) * n^(15/2)). - Vaclav Kotesovec, Apr 01 2021

A359363 Triangle read by rows. The coefficients of the Baxter polynomials p(0, x) = 1 and p(n, x) = x*hypergeom([-1 - n, -n, 1 - n], [2, 3], -x) for n >= 1.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 0, 1, 4, 1, 0, 1, 10, 10, 1, 0, 1, 20, 50, 20, 1, 0, 1, 35, 175, 175, 35, 1, 0, 1, 56, 490, 980, 490, 56, 1, 0, 1, 84, 1176, 4116, 4116, 1176, 84, 1, 0, 1, 120, 2520, 14112, 24696, 14112, 2520, 120, 1, 0, 1, 165, 4950, 41580, 116424, 116424, 41580, 4950, 165, 1
Offset: 0

Views

Author

Peter Luschny, Dec 28 2022

Keywords

Comments

This triangle is a member of a family of Pascal-like triangles. Let T(n, k, m) = sf(m)*F(n - 1) / (F(k - 1)*F(n - k)) if k > 0 and otherwise k^n, where F(n) = Product_{j=0..m} (n + j)! and sf(m) are the superfactorials A000178. The case m = 2 gives this triangle, some other cases are given in the crossreferences. See also A342889 for a related representation of generalized binomial coefficients.

Examples

			Triangle T(n, k) starts:
[0] 1
[1] 0, 1
[2] 0, 1,   1
[3] 0, 1,   4,    1
[4] 0, 1,  10,   10,     1
[5] 0, 1,  20,   50,    20,     1
[6] 0, 1,  35,  175,   175,    35,     1
[7] 0, 1,  56,  490,   980,   490,    56,    1
[8] 0, 1,  84, 1176,  4116,  4116,  1176,   84,   1
[9] 0, 1, 120, 2520, 14112, 24696, 14112, 2520, 120, 1
.
Let p = (p1, p2,..., pn) denote a permutation of {1, 2,..., n}. The pair (p(i), p(i+1)) is a 'rise' if p(i) < p(i+1). Additionally a conventional rise is counted at the beginning of p.
T(n, k) is the number of Baxter permutations of {1,2,...,n} with k rises. For example for n = 4, [T(n, k) for k = 0..n] = [0, 1, 10, 10, 1]. The permutations, with preceding number of rises, are:
.
1 [4, 3, 2, 1],  3 [2, 3, 4, 1],  2 [3, 4, 2, 1],  3 [2, 3, 1, 4],
2 [3, 2, 4, 1],  3 [2, 1, 3, 4],  2 [3, 2, 1, 4],  3 [1, 3, 4, 2],
2 [2, 4, 3, 1],  3 [1, 3, 2, 4],  2 [4, 2, 3, 1],  3 [3, 4, 1, 2],
2 [2, 1, 4, 3],  3 [3, 1, 2, 4],  2 [4, 2, 1, 3],  3 [1, 2, 4, 3],
2 [1, 4, 3, 2],  3 [1, 4, 2, 3],  2 [4, 1, 3, 2],  3 [4, 1, 2, 3],
2 [4, 3, 1, 2],  4 [1, 2, 3, 4].
		

Crossrefs

Special cases of the general formula: A097805 (m = 0), (0,1)-Pascal triangle; A090181 (m = 1), triangle of Narayana; this triangle (m = 2); A056940 (m = 3), with 1,0,0...; A056941 (m = 4), with 1,0,0...; A142465 (m = 5), with 1,0,0....
Variant: A056939. Diagonals: A000292, A006542, A047819.

Programs

  • Maple
    p := (n, x) -> ifelse(n = 0, 1, x*hypergeom([-1-n, -n, 1-n], [2, 3], -x)):
    seq(seq(coeff(simplify(p(n, x)), x, k), k = 0..n), n = 0..10);
    # Alternative:
    T := proc(n, k) local F; F := n -> n!*(n+1)!*(n+2)!;
    ifelse(k = 0, k^n, 2*F(n-1)/(F(k-1)*F(n-k))) end:
    for n from 0 to 9 do seq(T(n, k), k = 0..n) od;
  • PARI
    C=binomial;
    T(n, k) = if(n==0 && k==0, 1, ( C(n+1,k-1) * C(n+1,k) * C(n+1,k+1) ) / ( C(n+1,1) * C(n+1,2) ) );
    for(n=0,10,for(k=0,n,print1(T(n,k),", "));print());
    \\ Joerg Arndt, Jan 04 2024
    
  • Python
    from functools import cache
    from math import factorial
    @cache
    def A359363Row(n: int) -> list[int]:
        @cache
        def F(n: int): return factorial(n) ** 3 * ((n+1) * (n+1) * (n+2))
        if n == 0: return [1]
        return [0] + [(2*F(n-1))//(F(k-1) * F(n-k)) for k in range(1, n+1)]
    for n in range(0, 10): print(A359363Row(n))
    # Peter Luschny, Jan 04 2024
  • SageMath
    def A359363(n):
        if n == 0: return SR(1)
        h = x*hypergeometric([-1 - n, -n, 1 - n], [2, 3], -x)
        return h.series(x, n + 1).polynomial(SR)
    for n in range(10): print(A359363(n).list())
    def PolyA359363(n, t): return Integer(A359363(n)(x=t).n())
    # Peter Luschny, Jan 04 2024
    

Formula

T(n, k) = [x^k] p(n, x).
T(n, k) = 2*F(n-1)/(F(k-1)*F(n-k)) for k > 0 where F(n) = n!*(n+1)!*(n+2)!.
p(n, 1) = A001181(n), i.e. the Baxter numbers are the values of the Baxter polynomials at x = 1.
(-1)^(n + 1)*p(2*n + 1, -1) = A217800(n) .

A120258 Triangle of central coefficients of generalized Pascal-Narayana triangles.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 6, 3, 1, 1, 20, 20, 4, 1, 1, 70, 175, 50, 5, 1, 1, 252, 1764, 980, 105, 6, 1, 1, 924, 19404, 24696, 4116, 196, 7, 1, 1, 3432, 226512, 731808, 232848, 14112, 336, 8, 1, 1, 12870, 2760615, 24293412, 16818516, 1646568, 41580, 540, 9, 1
Offset: 0

Views

Author

Paul Barry, Jun 13 2006

Keywords

Comments

Columns are the central coefficients of the triangles T(n, k;r) with T(n, k;r)=Product{j=0..r, C(n+j, k+j)/C(n-k+j, j)}*[k<=n]; (r=0,A007318), (r=1;A001263),(r=2,A056939),(r=3,A056940),(r=4,A056941). Essentially A103905 as a number triangle with an extra diagonal of 1's. Central coefficients T(2n, n) are A008793. Row sums are A120259. Diagonal sums are A120260.

Examples

			Triangle begins:
  1;
  1,   1;
  1,   2,     1;
  1,   6,     3,     1;
  1,  20,    20,     4,    1;
  1,  70,   175,    50,    5,   1;
  1, 252,  1764,   980,  105,   6, 1;
  1, 924, 19404, 24696, 4116, 196, 7, 1;
  ...
		

Crossrefs

Row sums give A120259.

Programs

  • PARI
    T(n, k) = prod(j=0, k-1, binomial(2*n-2*k+j, n-k)/binomial(n-k+j, j)); \\ Seiichi Manyama, Apr 02 2021

Formula

Number triangle T(n, k)=[k<=n]*Product{j=0..k-1, C(2n-2k+j, n-k)/C(n-k+j, j)}
As a square array, this is T(n,m)=product{k=1..m, product{j=1..n, product{i=1..n, (i+j+k-1)/(i+j+k-2)}}}; - Paul Barry, May 13 2008

A342972 Triangle T(n,k) read by rows: T(n,k) = Product_{j=0..n-1} binomial(n+j,k)/binomial(k+j,k).

Original entry on oeis.org

1, 1, 1, 1, 3, 1, 1, 10, 10, 1, 1, 35, 105, 35, 1, 1, 126, 1176, 1176, 126, 1, 1, 462, 13860, 41580, 13860, 462, 1, 1, 1716, 169884, 1557270, 1557270, 169884, 1716, 1, 1, 6435, 2147145, 61408347, 184225041, 61408347, 2147145, 6435, 1
Offset: 0

Views

Author

Seiichi Manyama, Apr 01 2021

Keywords

Comments

Triangle read by rows: T(n,k) = generalized binomial coefficients (n,k)n where (n,k)_m is Product{j=1..k} binomial(n-j+m,m)/binomial(j-1+m,m).

Examples

			Triangle begins:
  1;
  1,    1;
  1,    3,       1;
  1,   10,      10,        1;
  1,   35,     105,       35,         1;
  1,  126,    1176,     1176,       126,        1;
  1,  462,   13860,    41580,     13860,      462,       1;
  1, 1716,  169884,  1557270,   1557270,   169884,    1716,    1;
  1, 6435, 2147145, 61408347, 184225041, 61408347, 2147145, 6435, 1;
		

Crossrefs

Row sums gives A342967.
Triangles of generalized binomial coefficients (n,k)_m (or generalized Pascal triangles) for m = 1,...,12: A007318 (Pascal), A001263, A056939, A056940, A056941, A142465, A142467, A142468, A174109, A342889, A342890, A342891.

Programs

  • Mathematica
    T[n_, k_] := Product[Binomial[n + i, k]/Binomial[k + i, k], {i, 0, n - 1}]; Table[T[n, k], {n, 0, 8}, {k, 0, n}] // Flatten (* Amiram Eldar, Apr 01 2021 *)
  • PARI
    T(n, k) = prod(j=0, n-1, binomial(n+j, k)/binomial(k+j, k));
    
  • PARI
    T(n, k) = prod(j=0, k-1, binomial(2*n-1, n+j)/binomial(2*n-1, j));
    
  • PARI
    f(n, k, m) = prod(j=1, k, binomial(n-j+m, m)/binomial(j-1+m, m));
    T(n, k) = f(n, k, n);

Formula

T(n,k) = Product_{j=0..k-1} binomial(2*n-1,n+j)/binomial(2*n-1,j).

A120257 Triangle of Hankel transforms of certain binomial sums.

Original entry on oeis.org

1, 2, -1, 3, -6, -1, 4, -20, -20, 1, 5, -50, -175, 70, 1, 6, -105, -980, 1764, 252, -1, 7, -196, -4116, 24696, 19404, -924, -1, 8, -336, -14112, 232848, 731808, -226512, -3432, 1, 9, -540, -41580, 1646568, 16818516, -24293412, -2760615, 12870, 1, 10, -825, -108900, 9343620, 267227532, -1447482465
Offset: 0

Views

Author

Paul Barry, Jun 13 2006

Keywords

Comments

Row k is the Hankel transform of Sum_{j=0..n} binomial(k+j, j). Absolute value is reversal of A103905. Diagonal and subdiagonals are essentially signed versions of the central coefficients of certain generalized Pascal-Narayana triangles (A007318, A001263, A056939, A056940, A056941).

Examples

			Triangle begins
  1;
  2,   -1;
  3,   -6,     -1;
  4,  -20,    -20,      1;
  5,  -50,   -175,     70,      1;
  6, -105,   -980,   1764,    252,      -1;
  7, -196,  -4116,  24696,  19404,    -924,    -1;
  8, -336, -14112, 232848, 731808, -226512, -3432, 1;
		

Crossrefs

Cf. A120258.

Programs

  • PARI
    T(n, k) = (-1)^((k+1)\2) * prod(j=0, n-k-1, binomial(2*k+2+j, k+1)/binomial(k+1+j, j)); \\ Michel Marcus, Jan 13 2022

Formula

T(n, k) = (cos(Pi*k/2) - sin(Pi*k/2)) * Product_{j=0..n-k-1} C(2k+2+j, k+1)/C(k+1+j, j).
Previous Showing 11-16 of 16 results.