1,1

Table of n, a(n) for n=1..76.

Reinhard Zumkeller, Products of largest prime factors of numbers <= n

a(n) = A000005(A104365(n)).

a[n_] := DivisorSigma[0, 1 + Product[FactorInteger[k][[-1, 1]], {k, 1, n}]]; Array[a, 76] (* Amiram Eldar, Feb 12 2020 *)

Cf. A000005, A064144, A104361, A104365, A104370.

Sequence in context: A003648 A003642 A100007 * A051702 A073130 A238267

Adjacent sequences: A104366 A104367 A104368 * A104370 A104371 A104372

nonn

Reinhard Zumkeller, Mar 06 2005

a(51)-a(76) from Amiram Eldar, Feb 12 2020

approved