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.

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A382435 a(n) = Sum_{k=0..n} ( binomial(n,k) - binomial(n,k-1) )^6.

Original entry on oeis.org

1, 1, 3, 129, 1587, 39443, 1125383, 30211457, 1107074979, 36214609683, 1433494688871, 54495716261011, 2275005440977063, 95146470595975399, 4170974287982618639, 185640304224109725569, 8492643748223480148419, 395051289603660979274339, 18726850582009755291702599
Offset: 0

Views

Author

Seiichi Manyama, Mar 25 2025

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(x, y) option remember; `if`(y<0 or y>x, 0,
         `if`(x=0, 1, add(b(x-1, y+j), j=[-1, 1])))
        end:
    a:= n-> 2*add(b(n, n-2*j)^6, j=0..n/2)-1:
    seq(a(n), n=0..18);  # Alois P. Heinz, Mar 25 2025
  • PARI
    a(n) = sum(k=0, n, (binomial(n, k)-binomial(n, k-1))^6);
    
  • Python
    from math import comb
    def A382435(n): return (sum((comb(n,j)*(m:=n-(j<<1)+1)//(m+j))**6 for j in range((n>>1)+1))<<1)-1 # Chai Wah Wu, Mar 25 2025

Formula

a(n) = Sum_{k=0..n} A080233(n,k)^6 = Sum_{k=0..n} A156644(n,k)^6.
a(n) = 2 * A382433(n) - 1.

A382443 a(n) = Sum_{k=0..n} binomial(n,k) * ( binomial(n,k) - binomial(n,k-1) )^4.

Original entry on oeis.org

1, 1, 4, 65, 566, 10912, 164032, 3237313, 62253130, 1314421886, 28392213224, 639799858304, 14785604868256, 350615631856960, 8485316740880384, 209179475361783233, 5239271305444731698, 133100429387161703962, 3424142506153260211720, 89090362800169426107070
Offset: 0

Views

Author

Seiichi Manyama, Mar 26 2025

Keywords

Crossrefs

Programs

  • Magma
    [&+[Binomial(n, k)* (Binomial(n, k) - Binomial (n, k-1))^4: k in [0..n]]: n in [0..21]]; // Vincenzo Librandi, Mar 29 2025
  • Mathematica
    Table[Sum[Binomial[n,k]*(Binomial[n,k]-Binomial[n,k-1])^4,{k,0,n}],{n,0,20}] (* Vincenzo Librandi, Mar 29 2025 *)
  • PARI
    a(n) = sum(k=0, n, binomial(n, k)*(binomial(n, k)-binomial(n, k-1))^4);
    

Formula

a(n) = Sum_{k=0..n} binomial(n,k)^2 * ( binomial(n,k) - binomial(n,k-1) )^3.
a(n) ~ 3 * 2^(5*n+6) / (Pi^2 * 5^(5/2) * n^4). - Vaclav Kotesovec, Mar 26 2025
Showing 1-2 of 2 results.