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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A333445 Table T(n,k) read by upward antidiagonals. T(n,k) = Product_{i=1..n} Sum_{j=1..k} (i-1)*k+j.

Original entry on oeis.org

1, 2, 3, 6, 21, 6, 24, 231, 90, 10, 120, 3465, 2160, 260, 15, 720, 65835, 71280, 10920, 600, 21, 5040, 1514205, 2993760, 633360, 39000, 1197, 28, 40320, 40883535, 152681760, 46868640, 3510000, 111321, 2156, 36, 362880, 1267389585, 9160905600, 4218177600
Offset: 1

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Author

Chai Wah Wu, Mar 23 2020

Keywords

Comments

T(n,k) is the minimum value of Product_{i=1..n} Sum_{j=1..k} r[(i-1)*k+j] among all permutations r of {1..kn}. For the maximum value see A333420.

Programs

  • Python
    def T(n,k): # T(n,k) for A333445
        c, l = 1, list(range(1,k*n+1,k))
        lt = list(l)
        for i in range(n):
            for j in range(1,k):
                lt[i] += l[i]+j
            c *= lt[i]
        return c

Formula

T(n,k) = k^(2n)*Gamma(n+(1+k)/2k)/Gamma((1+k)/2k).
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