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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.

A090225 T(n,k) = Points in n-dimensional lattice of side length k with at least one coordinate = k and GCD of all coordinates = 1.

Original entry on oeis.org

0, 0, 0, 0, 1, 0, 0, 0, 3, 0, 0, 0, 2, 7, 0, 0, 0, 4, 12, 15, 0, 0, 0, 4, 30, 50, 31, 0, 0, 0, 8, 42, 160, 180, 63, 0, 0, 0, 4, 84, 304, 750, 602, 127, 0, 0, 0, 12, 78, 656, 1890, 3304, 1932, 255, 0, 0, 0, 8, 162, 880, 4620, 10864, 14070, 6050, 511, 0, 0, 0, 12, 156, 1680, 8070
Offset: 0

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Author

Joshua Zucker, Nov 24 2003

Keywords

Examples

			T(3,2) = 12 because of the six permutations of (2,1,0) and three each of (2,1,1) and (2,2,1).
0;
0,  0;
0,  1,  0;
0,  0,  3,  0;
0,  0,  2,  7,  0;
0,  0,  4, 12, 15, 0;
0,  0,  4, 30, 50, 31,  0;
0,  0,  8, 42,160,180, 63, 0;
0,  0,  4, 84,304,750,602,127, 0;
0,  0, 12, 78,656,1890,3304,1932,255, 0;
		

Crossrefs

Cf. A090030.

Programs

  • Mathematica
    aux[n_, k_] := If[k == 0, 0, (k + 1)^n - k^n - Sum[aux[n, Divisors[k][[i]]], {i, 1, Length[Divisors[k]] - 1}]]

Formula

T(n, 0) = 0; T(n, k) = (k+1)^n - k^n - sum T(n, divisors of k)