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 A344878 a(n) is the least common multiple of numbers (2^(1+e2))-1 and those in the set (p_i^e_i)-1, when the odd part of n = Product (p_i^e_i), and e2 is the 2-adic valuation of n. 10
 1, 3, 2, 7, 4, 6, 6, 15, 8, 12, 10, 14, 12, 6, 4, 31, 16, 24, 18, 28, 6, 30, 22, 30, 24, 12, 26, 42, 28, 12, 30, 63, 10, 48, 12, 56, 36, 18, 12, 60, 40, 6, 42, 70, 8, 66, 46, 62, 48, 24, 16, 84, 52, 78, 20, 30, 18, 84, 58, 28, 60, 30, 24, 127, 12, 30, 66, 112, 22, 12, 70, 120, 72, 36, 24, 126, 30, 12, 78, 124, 80, 120 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Antti Karttunen, Table of n, a(n) for n = 1..10000 FORMULA If n = Product (p_i^e_i), then a(n) = LCM of values (p_i^(e_i+[p==2]))-1, where [ ] is the Iverson bracket. a(n) = lcm(A038712(n), a(A000265(n)). a(n) = A344875(n) / A344879(n). MATHEMATICA a[n_] := If[n == 1, 1, Module[{p, e}, LCM @@ Table[{p, e} = pe;      (p^(e + If[p == 2, 1, 0])) - 1, {pe, FactorInteger[n]}]]]; Array[a, 100] (* Jean-François Alcover, Jun 12 2021 *) PROG (PARI) A344878(n) = if(1==n, n, my(f=factor(n)~); lcm(vector(#f, i, (f[1, i]^(f[2, i]+(2==f[1, i]))-1)))); CROSSREFS Cf. A000265, A038712, A344875, A344879. Sequence in context: A316385 A341911 A341916 * A344875 A178910 A182651 Adjacent sequences:  A344875 A344876 A344877 * A344879 A344880 A344881 KEYWORD nonn AUTHOR Antti Karttunen, Jun 03 2021 STATUS approved

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Last modified December 9 03:23 EST 2021. Contains 349625 sequences. (Running on oeis4.)