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A291173 Totient superdeficient numbers: numbers n > 1 such that s(n)/n < s(m)/m for all m < n, where s(n) is the sum of iterated phi(n) (A092693). 1
2, 42, 90, 210, 630, 1050, 1470, 2310, 6930, 16170, 30030, 90090, 150150, 210210, 570570, 690690, 870870, 2072070, 3573570, 3993990, 4834830 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A variation of A286268 (Totient superabundant numbers).

LINKS

Table of n, a(n) for n=1..21.

EXAMPLE

The values of A092693(n)/n for n = 2, 42, 90 are 0.5, 0.452..., 0.433..., which are records of lowest values.

MATHEMATICA

Function[s, Flatten[First@Position[s, #] & /@ Union@Rest@FoldList[Max, 0, s]]]@ Table[n/(Total@FixedPointList[EulerPhi, n] - (n + 1)), {n, 2, 10^5}]+1 (* after Michael De Vlieger at A286268 and Alonso del Arte at A092693 *)

CROSSREFS

Cf. A092693, A286268, A291174.

Sequence in context: A076391 A130201 A076392 * A048373 A066563 A202865

Adjacent sequences:  A291170 A291171 A291172 * A291174 A291175 A291176

KEYWORD

nonn,more

AUTHOR

Amiram Eldar, Aug 19 2017

STATUS

approved

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Last modified November 13 19:25 EST 2018. Contains 317149 sequences. (Running on oeis4.)