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.

A027957 a(n) = greatest number in row n of array T given by A027948.

Original entry on oeis.org

1, 1, 2, 3, 7, 14, 25, 46, 97, 189, 344, 674, 1383, 2683, 4950, 9955, 20175, 39130, 72905, 148487, 298925, 580328, 1089343, 2233409, 4478413, 8705686, 16438345, 33822205, 67650909, 131688362, 251448212, 515037942, 1028483089, 2004688605, 3860656125, 7878708566, 15715540623, 30670416703, 59451560083
Offset: 0

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Crossrefs

Cf. A027948.

Programs

  • Magma
    A027948:= func< n,k | k eq n select 1 else (&+[Binomial(n-j, 2*(n-k-j)-1): j in [0..n-k]]) >;
    b:= func< n | [A027948(n,k): k in [0..n]] >;
    A027957:= func< n | Max( b(n) ) >;
    [A027957(n): n in [0..50]]; // G. C. Greubel, Jun 08 2025
  • Mathematica
    A027948[n_, k_]:= A027948[n, k]= If[k==n, 1, Sum[Binomial[n-j, 2*(n-k-j)-1], {j,0,n- k}]];
    b[n_]:= b[n]= Table[A027948[n,k], {k,0,n}]//Union;
    A027957[n_]:= Max[b[n]];
    Table[A027957[n], {n,0,50}] (* G. C. Greubel, Jun 07 2025 *)
  • SageMath
    @CachedFunction
    def A027948(n, k):
        if (k==n): return 1
        else: return sum(binomial(n-j, 2*(n-k-j)-1) for j in (0..n-k))
    def b(n): return sorted(set(flatten([ A027948(n,k) for k in range(n+1)])))
    def A027957(n): return max(b(n))
    print([A027957(n) for n in range(51)]) # G. C. Greubel, Jun 07 2025
    

Extensions

More terms added by G. C. Greubel, Jun 07 2025