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.

A027977 a(n) = greatest number in row n of array T given by A027960.

Original entry on oeis.org

1, 3, 4, 8, 15, 28, 54, 101, 199, 373, 743, 1404, 2801, 5353, 10636, 20495, 40615, 78753, 155793, 303553, 599801, 1173183, 2316317, 4544731, 8968421, 17641499, 34801731, 68602923, 135308317, 267203186, 526966454, 1042217402, 2055373383, 4070330014, 8027429651, 15914813448, 31389204737, 62291326036, 122871494899
Offset: 0

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Keywords

Crossrefs

Cf. A027960.

Programs

  • Mathematica
    T[n_, k_]:= T[n, k]= If[k<0 || k>2*n, 0, If[k==0 || k==2*n, 1, If[k==1, 3, T[n-1, k-2] + T[n-1, k-1]]]]; (* T = A027960 *)
    b[n_]:= b[n]= Table[T[n,k], {k,0,2*n}]//Union;
    A027977[n_]:= Max[b[n]];
    Table[A027977[n], {n,0,50}] (* G. C. Greubel, Jun 07 2025 *)
  • SageMath
    @CachedFunction
    def T(n, k): # T = A027960
        if (k<0 or k>2*n): return 0
        elif (k==0 or k==2*n): return 1
        elif (k==1): return 3
        else: return T(n-1, k-2) + T(n-1, k-1)
    def b(n): return sorted(set(flatten([T(n,k) for k in range(2*n+1)])))
    def A027977(n): return max(b(n))
    print([A027977(n) for n in range(51)]) # G. C. Greubel, Jun 07 2025

Extensions

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