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.

A280470 Triangle A106534 with reversed rows.

Original entry on oeis.org

1, 1, 2, 2, 3, 5, 5, 7, 10, 15, 14, 19, 26, 36, 51, 42, 56, 75, 101, 137, 188, 132, 174, 230, 305, 406, 543, 731, 429, 561, 735, 965, 1270, 1676, 2219, 2950, 1430, 1859, 2420, 3155, 4120, 5390, 7066, 9285, 12235, 4862, 6292, 8151, 10571, 13726, 17846, 23236, 30302, 39587, 51822, 16796, 21658, 27950, 36101, 46672
Offset: 0

Views

Author

Tony Foster III, Jan 03 2017

Keywords

Examples

			Fibonacci Determinant Triangle:
    1;
    1,    2;
    2,    3,    5;
    5,    7,   10,   15;
   14,   19,   26,   36,   51;
   42,   56,   75,  101,  137,  188;
  132,  174,  230,  305,  406,  543,  731;
  429,  561,  735,  965, 1270, 1676, 2219, 2950;
  ...
		

Crossrefs

Programs

  • Magma
    &cat [[&+[Binomial(k,j)*Catalan(n-j): j in [0..k]]: k in [0..n]]: n in [0..10]]; // Bruno Berselli, Mar 07 2017
  • Mathematica
    Table[Sum[Binomial[k, j] CatalanNumber[n - j], {j, 0, k}], {n, 0, 10}, {k, 0, n}] // Flatten (* Michael De Vlieger, Mar 08 2017 *)
  • PARI
    C(n)=binomial(2*n,n)/(n+1);
    T(n,k)=sum(j=0,k,binomial(k,j)*C(n-j));
    for(n=0,10,for(k=0,n,print1(T(n,k),", "));print()); \\ Joerg Arndt, Jan 15 2017
    

Formula

T(n,k) = Sum_{j=0..k} binomial(k,j) * A000108(n-j). - Joerg Arndt, Jan 15 2017

A059346 Difference array of Catalan numbers A000108 read by antidiagonals.

Original entry on oeis.org

1, 0, 1, 1, 1, 2, 1, 2, 3, 5, 3, 4, 6, 9, 14, 6, 9, 13, 19, 28, 42, 15, 21, 30, 43, 62, 90, 132, 36, 51, 72, 102, 145, 207, 297, 429, 91, 127, 178, 250, 352, 497, 704, 1001, 1430, 232, 323, 450, 628, 878, 1230, 1727, 2431, 3432, 4862, 603, 835, 1158, 1608, 2236, 3114
Offset: 0

Views

Author

N. J. A. Sloane, Jan 27 2001

Keywords

Examples

			Array starts:
      1       1       2       5      14      42     132     429
      0       1       3       9      28      90     297    1001
      1       2       6      19      62     207     704    2431
      1       4      13      43     145     497    1727    6071
      3       9      30     102     352    1230    4344   15483
      6      21      72     250     878    3114   11139   40143
     15      51     178     628    2236    8025   29004  105477
     36     127     450    1608    5789   20979   76473  280221
     91     323    1158    4181   15190   55494  203748  751422
    232     835    3023   11009   40304  148254  547674 2031054
    603    2188    7986   29295  107950  399420 1483380 5527750
Triangle starts:
  1;
  0,  1;
  1,  1,  2;
  1,  2,  3,  5;
  3,  4,  6,  9, 14;
		

Crossrefs

Top row is A000108, leading diagonals give A005043, A001006, A005554.
Row sums are A106640.

Programs

  • Maple
    T := (n,k) -> (-1)^(n-k)*binomial(2*k,k)*hypergeom([k-n,k+1/2], [k+2], 4)/(k+1): seq(seq(simplify(T(n,k)), k=0..n), n=0..10);
    # Peter Luschny, Aug 16 2012, updated May 25 2021
  • Mathematica
    max = 11; t = Table[ Differences[ Table[ CatalanNumber[k], {k, 0, max}], n], {n, 0, max}]; Flatten[ Table[t[[n-k+1, k]], {n, 1, max}, {k, 1, n}]] (* Jean-François Alcover, Nov 15 2011 *)
  • Sage
    def T(n, k) :
        if k > n : return 0
        if n == k : return binomial(2*n, n)/(n+1)
        return T(n-1, k) - T(n, k+1)
    A059346 = lambda n,k: (-1)^(n-k)*T(n, k)
    for n in (0..5): [A059346(n,k) for k in (0..n)] # Peter Luschny, Aug 16 2012

Formula

T(n, k) = (-1)^(n-k)*binomial(2*k,k)/(k+1)*hypergeometric([k-n, k+1/2],[k+2], 4). - Peter Luschny, Aug 16 2012

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Feb 16 2001

A283298 Diagonal of the Euler-Seidel matrix for the Catalan numbers.

Original entry on oeis.org

1, 3, 26, 305, 4120, 60398, 934064, 15000903, 247766620, 4182015080, 71816825856, 1250772245698, 22039796891026, 392213323252200, 7038863826811100, 127248841020380105, 2315130641074743540, 42358284517663463380, 778876539384226875800
Offset: 0

Views

Author

R. J. Mathar, Jul 20 2017

Keywords

Crossrefs

Central elements of rows in A106534, A280470.
Cf. A000108.

Programs

  • Maple
    A000108 := n-> binomial(2*n, n)/(n+1):
    A283298 := proc(n)
        add(binomial(n,i)*A000108(n+i),i=0..n) ;
    end proc:
    seq(A283298(n),n=0..30) ;
  • Mathematica
    Table[Sum[Binomial[n, i] CatalanNumber[n + i], {i, 0, n}], {n, 0, 50}] (* Indranil Ghosh, Jul 20 2017 *)
  • PARI
    C(n) = binomial(2*n,n)/(n+1); \\ A000108
    a(n) = sum(i=0, n, binomial(n,i) * C(n+i)); \\ Michel Marcus, Nov 12 2022
  • Python
    from sympy import binomial, catalan
    def a(n): return sum(binomial(n, i)*catalan(n + i) for i in range(n + 1))
    print([a(n) for n in range(51)]) # Indranil Ghosh, Jul 20 2017
    

Formula

a(n) = Sum_{i=0..n} binomial(n,i) * A000108(n+i).
D-finite with recurrence 2*n*(2*n+1)*(9*n-11)*a(n) +(-711*n^3+1589*n^2-986*n+144)*a(n-1) -10*(n-1)*(9*n-2)*(2*n-3)*a(n-2)=0.
a(n) ~ 2^(2*n) * 5^(n + 3/2) / (27 * sqrt(Pi) * n^(3/2)). - Vaclav Kotesovec, Sep 01 2025
Showing 1-3 of 3 results.