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 A365636 a(n) is the smallest multiple of n that is a term of A072873. 2
 1, 4, 27, 4, 3125, 108, 823543, 16, 27, 12500, 285311670611, 108, 302875106592253, 3294172, 84375, 16, 827240261886336764177, 108, 1978419655660313589123979, 12500, 22235661, 1141246682444, 20880467999847912034355032910567, 432, 3125, 1211500426369012, 27, 3294172 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Amiram Eldar, Table of n, a(n) for n = 1..388 FORMULA Multiplicative with a(p^e) = p^(p*ceiling(e/p)). a(n) = n * A365637(n). a(n) >= n with equality if and only if n is in A072873. Sum_{n>=1} 1/a(n) = Product_{p prime} (1 + p/(p^p-1)) = 1.86196549645040699446... . MATHEMATICA f[p_, e_] := p^(Ceiling[e/p]*p); a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 30] PROG (PARI) a(n) = {my(f = factor(n)); prod(i = 1, #f~, f[i, 1]^(f[i, 1] * ceil(f[i, 2] / f[i, 1]))); } CROSSREFS Cf. A072873, A365637. Sequence in context: A144990 A102199 A351366 * A345311 A125723 A094543 Adjacent sequences: A365633 A365634 A365635 * A365637 A365638 A365639 KEYWORD nonn,easy,mult AUTHOR Amiram Eldar, Sep 14 2023 EXTENSIONS Data, formulas and codes corrected by Amiram Eldar, Feb 15 2024 STATUS approved

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Last modified August 9 01:26 EDT 2024. Contains 375024 sequences. (Running on oeis4.)