A123708 a(n) = sum of unsigned elements in row n of triangle A123706.

1, 3, 3, 4, 3, 5, 3, 4, 4, 7, 3, 8, 3, 7, 7, 4, 3, 8, 3, 8, 7, 7, 3, 8, 4, 7, 4, 8, 3, 13, 3, 4, 7, 7, 7, 8, 3, 7, 7, 8, 3, 13, 3, 8, 8, 7, 3, 8, 4, 8, 7, 8, 3, 8, 7, 8, 7, 7, 3, 16, 3, 7, 8, 4, 7, 13, 3, 8, 7, 15, 3, 8, 3, 7, 8, 8, 7, 13, 3, 8, 4, 7, 3, 16, 7, 7, 7, 8, 3, 16, 7, 8, 7, 7, 7, 8, 3, 8, 8, 8, 3, 13

Offset

1,2

Comments

Triangle A123706 is the matrix inverse of triangle A010766, where A010766(n,k) = [n/k].

Links

G. C. Greubel, Table of n, a(n) for n = 1..1000

Mathematica

t[n_, k_] := If[Divisible[n, k], MoebiusMu[n/k], 0] - If[Divisible[n, k + 1], MoebiusMu[n/(k + 1)], 0]; Table[Sum[Abs[t[n, k]], {k, 1, n}], {n, 1, 50}] (* G. C. Greubel, Oct 26 2017 *)

Prog

(PARI) {a(n)=local(M=matrix(n, n, r, c, if(r>=c, floor(r/c)))^-1); sum(k=1, n, abs(M[n, k]))}

Crossrefs

Cf. A123706, A123707, A123709; A010766.

Sequence in context: A161357 A138372 A316662 * A350501 A102302 A130896

Adjacent sequences: A123705 A123706 A123707 * A123709 A123710 A123711

Keyword

nonn

Author

Paul D. Hanna, Oct 09 2006

Status

approved