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 A365635 The largest divisor of n that is a term of A048102. 2
 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 27, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 27, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 27, 1, 1, 4, 1, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 Vaclav Kotesovec, Graphs - the asymptotic ratio (10^7, 10^8 and 10^9 terms). FORMULA Multiplicative with a(p^e) = 1 if e < p and p^p otherwise. a(n) <= n with equality if and only if n is in A048102. a(n) >= 1 with equality if and only if n is in A048103. Dirichlet g.f.: zeta(s) * Product_{p prime} (1 + (p^p-1)/p^(p*s)). MATHEMATICA f[p_, e_] := p^If[e < p, 0, p]; a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] PROG (PARI) a(n) = {my(f = factor(n)); prod(i = 1, #f~, if(f[i, 2] < f[i, 1], 1, f[i, 1]^f[i, 1])); } CROSSREFS Cf. A048102, A048103, A327939, A365634. Sequence in context: A193512 A366524 A366523 * A276330 A234957 A327939 Adjacent sequences: A365632 A365633 A365634 * A365636 A365637 A365638 KEYWORD nonn,easy,mult AUTHOR Amiram Eldar, Sep 14 2023 STATUS approved

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Last modified September 11 09:25 EDT 2024. Contains 375815 sequences. (Running on oeis4.)