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A327785
Square array read by antidiagonals: A(n,k) = Sum_{d|n} (k/d), (n>=1, k>=0), where (m/n) is the Kronecker symbol.
1
1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 0, 0, 3, 1, 1, 1, 1, 1, 2, 1, 1, 0, 2, 1, 0, 4, 1, 1, 1, 0, 1, 0, 0, 2, 1, 1, 2, 1, 1, 2, 0, 2, 4, 1, 1, 1, 2, 1, 1, 2, 0, 1, 3, 1, 1, 2, 0, 3, 2, 0, 2, 0, 1, 4, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 0, 2, 1, 1, 0, 2, 3, 0, 4, 0, 0, 3, 0, 0, 6, 1
OFFSET
1,5
LINKS
EXAMPLE
Square array begins:
1, 1, 1, 1, 1, 1, 1, 1, ...
1, 2, 1, 0, 1, 0, 1, 2, ...
1, 2, 0, 1, 2, 0, 1, 2, ...
1, 3, 1, 1, 1, 1, 1, 3, ...
1, 2, 0, 0, 2, 1, 2, 0, ...
1, 4, 0, 0, 2, 0, 1, 4, ...
1, 2, 2, 0, 2, 0, 0, 1, ...
1, 4, 1, 0, 1, 0, 1, 4, ...
MATHEMATICA
A[n_, k_] := Sum[KroneckerSymbol[k, d], {d, Divisors[n]}];
Table[A[n - k, k], {n, 1, 13}, {k, n - 1, 0, -1}] // Flatten (* Jean-François Alcover, Sep 25 2019 *)
KEYWORD
nonn,tabl
AUTHOR
Seiichi Manyama, Sep 25 2019
STATUS
approved