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A302572 Unitary barely deficient numbers: unitary deficient numbers n such that usigma(n)/n > usigma(m)/m for all unitary deficient numbers m < n, where usigma(n) being the sum of the unitary divisors of n (A034448). 1
1, 2, 10, 84, 110, 1155, 6490, 34320, 55335, 80652, 163212, 449295, 676390, 1360810, 1503370, 1788490, 3214090, 22627605, 32062485, 35604492, 103712410, 365690892, 615206030, 815634435 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..24.

EXAMPLE

The values of usigma(n)/n are 1, 1.5, 1.8, 1.904..., 1.963..., 1.994...

MATHEMATICA

usigma[n_] := If[n == 1, 1, Times @@ (1 + Power @@@ FactorInteger[n])]; seq = {}; r = 0; Do[s = usigma[n]/n; If[s < 2 && s > r, AppendTo[seq, n]; r = s], {n, 1, 1000000}]; seq

CROSSREFS

Cf. A034448, A071927, A302570.

Sequence in context: A298690 A101878 A121194 * A121516 A024491 A250117

Adjacent sequences:  A302569 A302570 A302571 * A302573 A302574 A302575

KEYWORD

nonn,more

AUTHOR

Amiram Eldar, Apr 10 2018

STATUS

approved

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Last modified November 11 15:51 EST 2019. Contains 329019 sequences. (Running on oeis4.)