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 11-14 of 14 results.

A234464 5*binomial(8*n+5, n)/(8*n+5).

Original entry on oeis.org

1, 5, 50, 630, 8925, 135751, 2165800, 35759900, 605902440, 10475490875, 184068392508, 3277575482090, 59012418601500, 1072549882307925, 19651558477204200, 362592313327737592, 6731396321743423000, 125645122201355505000, 2356570385677427920770
Offset: 0

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Author

Tim Fulford, Dec 26 2013

Keywords

Comments

Fuss-Catalan sequence is a(n,p,r) = r*binomial(np+r,n)/(np+r), this is the case p=8, r=5.

Crossrefs

Programs

  • Magma
    [5*Binomial(8*n+5, n)/(8*n+5): n in [0..30]]; // Vincenzo Librandi, Dec 26 2012
  • Mathematica
    Table[5 Binomial[8 n + 5, n]/(8 n + 5), {n, 0, 40}] (* Vincenzo Librandi, Dec 26 2013 *)
  • PARI
    a(n) = 5*binomial(8*n+5,n)/(8*n+5);
    
  • PARI
    {a(n)=local(B=1); for(i=0, n, B=(1+x*B^(8/5))^5+x*O(x^n)); polcoeff(B, n)}
    

Formula

G.f. satisfies: B(x) = {1 + x*B(x)^(p/r)}^r, where p=8, r=5.

A230390 5*binomial(8*n+10,n)/(4*n+5).

Original entry on oeis.org

1, 10, 125, 1760, 26650, 423752, 6978510, 117998400, 2036685765, 35738059500, 635627275767, 11433154297760, 207621482341000, 3801296492623560, 70092637731997100, 1300500163756675200, 24262157874835233000, 454847339247972377850, 8564398318045559667475
Offset: 0

Views

Author

Tim Fulford, Dec 28 2013

Keywords

Comments

Fuss-Catalan sequence is a(n,p,r) = r*binomial(np+r,n)/(np+r), this is the case p=8, r=10.

Crossrefs

Programs

  • Magma
    [5*Binomial(8*n+10, n)/(4*n+5): n in [0..30]];
  • Mathematica
    Table[5 Binomial[8 n + 10, n]/(4 n + 5), {n, 0, 30}]
  • PARI
    a(n) = 5*binomial(8*n+10,n)/(4*n+5);
    
  • PARI
    {a(n)=local(B=1); for(i=0, n, B=(1+x*B^(4/5))^10+x*O(x^n)); polcoeff(B, n)}
    

Formula

G.f. satisfies: B(x) = {1 + x*B(x)^(p/r)}^r, where p=8, r=10.

A386396 a(0) = 1; a(n) = Sum_{k=0..floor((n-1)/7)} a(7*k) * a(n-1-7*k).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 7, 8, 17, 27, 38, 50, 63, 77, 92, 200, 325, 468, 630, 812, 1015, 1240, 2728, 4488, 6545, 8925, 11655, 14763, 18278, 40508, 67158, 98728, 135751, 178794, 228459, 285384, 635628, 1059380, 1566040, 2165800, 2869685, 3689595, 4638348
Offset: 0

Views

Author

Seiichi Manyama, Jul 20 2025

Keywords

Crossrefs

Programs

  • PARI
    apr(n, p, r) = r*binomial(n*p+r, n)/(n*p+r);
    a(n) = apr(n\7, 8, n%7+1);

Formula

For k=0..6, a(7*n+k) = (k+1) * binomial(8*n+k+1,n)/(8*n+k+1).
G.f. A(x) satisfies A(x) = 1/(1 - x * Product_{k=0..6} A(w^k*x)), where w = exp(2*Pi*i/7).

A386558 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals: A(n,k) = binomial((k+1)*n+k-1,n)/(n+1).

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 2, 2, 0, 1, 3, 7, 5, 0, 1, 4, 15, 30, 14, 0, 1, 5, 26, 91, 143, 42, 0, 1, 6, 40, 204, 612, 728, 132, 0, 1, 7, 57, 385, 1771, 4389, 3876, 429, 0, 1, 8, 77, 650, 4095, 16380, 32890, 21318, 1430, 0, 1, 9, 100, 1015, 8184, 46376, 158224, 254475, 120175, 4862, 0
Offset: 0

Views

Author

Seiichi Manyama, Jul 26 2025

Keywords

Examples

			Square array begins:
  1,   1,    1,     1,      1,      1,       1, ...
  0,   1,    2,     3,      4,      5,       6, ...
  0,   2,    7,    15,     26,     40,      57, ...
  0,   5,   30,    91,    204,    385,     650, ...
  0,  14,  143,   612,   1771,   4095,    8184, ...
  0,  42,  728,  4389,  16380,  46376,  109668, ...
  0, 132, 3876, 32890, 158224, 548340, 1533939, ...
		

Crossrefs

Columns k=0..10 give A000007, A000108, A006013, A006632, A118971, A130564(n+1), A130565(n+1), A234466, A234513, A234573, A235340.
Main diagonal gives A177784(n+1).
Cf. A162382.

Programs

  • PARI
    a(n, k) = binomial((k+1)*n+k-1, n)/(n+1);

Formula

For k > 0, A(n,k) = r * binomial(n*p+r,n)/(n*p+r), the Fuss-Catalan number with p=k+1 and r=k.
G.f. of column k: (1/x) Series_Reverion( x*(1-x)^k ).
Previous Showing 11-14 of 14 results.