A073356 Greatest common divisor of squarefree kernel of n and sum of squarefree kernels of numbers <= n.

1, 1, 3, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 5, 2, 17, 1, 1, 2, 7, 1, 1, 2, 1, 1, 1, 2, 1, 3, 1, 2, 3, 1, 1, 6, 1, 1, 3, 2, 1, 3, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 53, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 3, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 3, 1, 2, 1, 1, 1, 14, 1, 1, 1, 2, 1, 1, 7, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1

Offset: 1

Author

Reinhard Zumkeller, Jul 29 2002

Keywords

• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A007947, A073355.

Programs

Mathematica

rad[n_] := Times @@ FactorInteger[n][[;; , 1]]; seq[nmax_] := Module[{v = Array[rad, nmax]}, GCD[v, Accumulate[v]]]; seq[100] (* Amiram Eldar, Apr 06 2025 *)

Formula

a(n) = GCD(A007947(n), A073355(n)).