A104353 Sum of divisors of A104350(n).
1, 3, 12, 28, 168, 546, 4368, 9360, 28800, 148800, 1785600, 5401440, 75620160, 538793640, 2711348640, 5603453856, 100862169408, 303420079872, 6068401597440, 30380907997440, 213199354368000, 2362959510912000, 56711028261888000, 170288884313856000
Offset: 1
Keywords
Links
- Amiram Eldar, Table of n, a(n) for n = 1..640
- Reinhard Zumkeller, Products of largest prime factors of numbers <= n.
Programs
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Mathematica
DivisorSigma[1, FoldList[Times, Array[FactorInteger[#][[-1, 1]] &, 30]]] (* Amiram Eldar, Apr 08 2024 *)
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PARI
gpf(n) = {my(p = factor(n)[, 1]); p[#p];} a(n) = sigma(prod(k = 2, n, gpf(k))); \\ Amiram Eldar, Apr 08 2024
Extensions
a(14), a(21) corrected by Georg Fischer, Feb 28 2023