A348979 Denominator of ratio A332993(n) / sigma(n).

1, 1, 1, 1, 1, 6, 1, 1, 1, 9, 1, 14, 1, 12, 8, 1, 1, 39, 1, 7, 32, 18, 1, 30, 1, 21, 1, 28, 1, 24, 1, 1, 16, 27, 48, 91, 1, 30, 56, 45, 1, 96, 1, 14, 13, 36, 1, 62, 1, 31, 24, 49, 1, 60, 72, 60, 80, 45, 1, 56, 1, 48, 26, 1, 84, 48, 1, 21, 32, 144, 1, 195, 1, 57, 62, 70, 96, 168, 1, 31, 1, 63, 1, 224, 108, 66, 40, 90

Offset

1,6

Comments

See comments in A348978.

Links

Antti Karttunen, Table of n, a(n) for n = 1..16384

Index entries for sequences related to sigma(n)

Formula

a(n) = A000203(n) / A348977(n) = A000203(n) / gcd(A000203(n), A332993(n)).

Mathematica

f[n_] := n/FactorInteger[n][[1, 1]]; g[1] = 1; g[n_] := g[n] = n + g[f[n]]; a[n_] := Denominator[g[n]/DivisorSigma[1, n]]; Array[a, 100] (* Amiram Eldar, Nov 06 2021 *)

Prog

(PARI)
A332993(n) = if(1==n, n, n + A332993(n/vecmin(factor(n)[, 1])));
A348979(n) = { my(s=sigma(n)); (s/gcd(s, A332993(n))); };

Crossrefs

Cf. A000203, A332993, A333783, A348977, A348978 (numerators).

Cf. also A348988, A348989.

Sequence in context: A063919 A308135 A072815 * A080304 A340677 A340679

Adjacent sequences: A348976 A348977 A348978 * A348980 A348981 A348982

Keyword

nonn,frac

Author

Antti Karttunen, Nov 06 2021

Status

approved