A292705 Nonsquarefree unitary abundant numbers.

150, 294, 420, 630, 660, 726, 750, 780, 840, 924, 990, 1014, 1020, 1050, 1092, 1140, 1170, 1380, 1386, 1428, 1470, 1530, 1596, 1638, 1650, 1710, 1734, 1740, 1860, 1890, 1950, 2058, 2070, 2142, 2166, 2220, 2394, 2460, 2550, 2580, 2610, 2790, 2820, 2850, 2940

Offset: 1

Author

Amiram Eldar, Sep 21 2017

Keywords

• nonn

Comments

Most unitary abundant numbers are squarefree. For example, there are 70030 unitary abundant numbers below 10^6, and only 14685 are nonsquarefree.

The odd terms of this sequence are A129486.

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A013929, A034683, A129486.

Programs

Mathematica

usigma[n_]:=If[n==1, 1, Times @@ (1 + Power @@@ FactorInteger[n])];
aQ[n_]:=!SquareFreeQ[n] && usigma[n] > 2 n; Select[Range[10^4], aQ]