A349838 Irregular table read by rows; the n-th row contains in ascending order the integers m > 1 such that sigma(m) = tau(m)^n; the first row contains 1.

1, 3, 7, 217, 2667, 31, 889, 27559, 3937, 172011, 677207307, 127, 1777447, 225735769, 57337, 11010027, 12189603, 3612185689, 698915267211, 253921, 113770279, 116522119, 29587412978599, 917497, 1040257, 931892355289, 954432676729, 811637999283747

Offset

1,2

Comments

The n-th row has A349837(n) terms.

As a flat sequence, this is a permutation of A051281.

Links

Table of n, a(n) for n=1..28.

Rémy Sigrist, PARI program for A349838

Formula

T(n, 1) = A349006(n) when A349837(n) > 0.

T(n, A349837(n)) = A349007(n) when A349837(n) > 0.

A334455(T(n, k)) = n.

Example

Table begins:
    1;
    3;
    7;
    217, 2667;
    31, 889, 27559;
    3937, 172011, 677207307;
    127, 1777447, 225735769;
    57337, 11010027, 12189603, 3612185689, 698915267211;
    253921, 113770279, 116522119, 29587412978599;
    917497, 1040257, 931892355289, 954432676729, 811637999283747;
    ...

Prog

(PARI) See Links section.

Crossrefs

Cf. A000005 (tau), A000203 (sigma), A051281, A334455, A349006, A349007, A349837.

Sequence in context: A132564 A057619 A349006 * A179859 A061422 A206333

Adjacent sequences: A349835 A349836 A349837 * A349839 A349840 A349841

Keyword

nonn,tabf

Author

Rémy Sigrist, Dec 01 2021

Status

approved