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A051522 Least positive integer with exactly n representations as k/d(k), where d(k) = number of divisors of k. 0
18, 4, 1, 3, 11264, 64000, 82944, 27599616 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

27599616 is the only number < 4*10^7 with exactly 7 representations as k/d(k). - Donovan Johnson, Sep 29 2012

LINKS

Table of n, a(n) for n=0..7.

EXAMPLE

Contribution from Donovan Johnson, Sep 29 2012: (Start)

a(1) = A051278(1) = 4. k/d(k) = 4 for exactly 1 k value: 36.

a(2) = A051279(1) = 1. k/d(k) = 1 for exactly 2 k values: 1 and 2.

a(3) = A051280(1) = 3. k/d(k) = 3 for exactly 3 k values: 9, 18 and 24.

a(4) = A217125(1) = 11264. k/d(k) = 11264 for exactly 4 k values: 360448, 585728, 630784 and 1115136.

a(5) = A217126(1) = 64000. k/d(k) = 64000 for exactly 5 k values: 4096000, 6656000, 7040000, 7168000 and 11520000.

a(6) = A217127(1) = 82944. k/d(k) = 82944 for exactly 6 k values: 7962624, 12939264, 13271040, 13934592, 21565440 and 23224320.

a(7) = 27599616. k/d(k) = 27599616 for exactly 7 k values: 10598252544, 17222160384, 17663754240, 18215746560, 18546941952, 28703600640 and 30911569920. (End)

CROSSREFS

Cf. A051278, A051279, A051280, A217125, A217126, A217127.

Sequence in context: A317318 A321263 A040313 * A134906 A018815 A014974

Adjacent sequences:  A051519 A051520 A051521 * A051523 A051524 A051525

KEYWORD

nonn,hard

AUTHOR

David W. Wilson

EXTENSIONS

a(4)-a(6) verified and a(7) added by Donovan Johnson, Sep 29 2012

STATUS

approved

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Last modified January 21 05:39 EST 2020. Contains 331104 sequences. (Running on oeis4.)