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

Author

Paul D. Hanna, Oct 09 2006

Keywords

• nonn

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

Crossrefs

Cf. A123706, A123707, A123709; A010766.

Programs

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 *)

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]))}