

A129498


Unitary abundancy of nth unitary abundant number: usigma(k)2k if this is > 0.


2



12, 12, 12, 4, 12, 12, 12, 12, 12, 12, 12, 156, 12, 12, 12, 12, 12, 12, 204, 12, 12, 228, 12, 120, 12, 12, 228, 12, 12, 276, 12, 252, 300, 12, 12, 12, 180, 12, 12, 120, 12, 348, 300, 12, 12, 12, 188, 120, 12, 324, 12, 12, 48, 300, 420, 12, 12, 196, 72, 444, 12, 372
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OFFSET

1,1


COMMENTS

The transforms of this sequence are discussed in A129499.


LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000
Eric Weisstein's World of Mathematics, Unitary Divisor.


FORMULA

A034448(k)2k = A034460(k)k, whenever these are positive.
a(n) = A129468(A034683(n)).  Amiram Eldar, Jun 18 2019


EXAMPLE

The fourth unitary abundant number is 70. As the unitary divisors of 70 are 1, 2, 5, 7, 10, 14, 35 and 70, we have a(4) = 1+2+5+7+10+14+35+702 * 70 = 4.


MATHEMATICA

uab[1]=1; uab[n_] := Times @@ (1 + Power @@@ FactorInteger[n])  2n; seq={}; Do[u=uab[n]; If[u>0, AppendTo[seq, u]], {n, 1, 1000}]; seq (* Amiram Eldar, Jun 18 2019 *)


CROSSREFS

Cf. A034448, A034460, A129468, A034683, A129499.
Sequence in context: A112124 A268916 A069873 * A010851 A123896 A122878
Adjacent sequences: A129495 A129496 A129497 * A129499 A129500 A129501


KEYWORD

easy,nonn


AUTHOR

Ant King, Apr 20 2007


STATUS

approved



