A388274 a(n) = A053585(sigma(n)).

1, 3, 4, 7, 3, 3, 8, 5, 13, 9, 3, 7, 7, 3, 3, 31, 9, 13, 5, 7, 32, 9, 3, 5, 31, 7, 5, 7, 5, 9, 32, 7, 3, 27, 3, 13, 19, 5, 7, 5, 7, 3, 11, 7, 13, 9, 3, 31, 19, 31, 9, 49, 27, 5, 9, 5, 5, 5, 5, 7, 31, 3, 13, 127, 7, 9, 17, 7, 3, 9, 9, 13, 37, 19, 31, 7, 3, 7, 5, 31, 121, 7, 7, 7, 27, 11, 5, 5, 5, 13, 7, 7, 128, 9

Offset

1,2

Links

Antti Karttunen, Table of n, a(n) for n = 1..65537

Index entries for sequences related to sigma(n).

Formula

a(n) = A071190(n)^(A071178(A000203(n))).

Mathematica

A388274[n_] := Power @@ Last[FactorInteger[DivisorSigma[1, n]]];
Array[A388274, 100] (* Paolo Xausa, Sep 20 2025 *)

Prog

(PARI)
A053585(n) = if(n>1, my(f=factor(n)); f[#f~, 1]^f[#f~, 2], 1);
A388274(n) = A053585(sigma(n));

Crossrefs

Cf. A000203, A053585, A071178, A071190, A388275.

Sequence in context: A130880 A026248 A082089 * A089961 A359954 A316498

Adjacent sequences: A388271 A388272 A388273 * A388275 A388276 A388277

Keyword

nonn,easy

Author

Antti Karttunen, Sep 20 2025

Status

approved