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A061072 Smallest integer with A002191(n) divisors, i.e., the number of divisors equals the sum of the divisors of a different number. 0
1, 4, 6, 12, 64, 24, 60, 4096, 192, 144, 180, 240, 360, 960, 720, 1073741824, 840, 1260, 786432, 36864, 1680, 2880, 15360, 2520, 6300, 6720, 2359296, 5040, 3221225472, 14400, 983040, 10080, 206158430208, 184320, 15120, 20160, 25200 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..36.

FORMULA

A000005(a(n)) = A002191(n). I.e., if function A000005 is applied to this sequence, then values of A002191 are obtained. These terms are taken from A005179.

a(n) = A005179(A002191(n)). - David Wasserman, Jun 06 2002

EXAMPLE

For all values of sigma(x), i.e., of A002191, the smallest number with identical number of divisors is found at A005179(sigma(x)). E.g., 8 = A002191(6) is a possible divisor sum. The smallest number which has 8 divisors is 24 = A005179(8). See also comment to A008864, with special solutions of equation: sigma(x) = tau(y) = A000203(x) = A000005(y).

CROSSREFS

Cf. A000005, A000203, A002191, A005179, A008864.

Sequence in context: A114413 A068507 A133454 * A130435 A028444 A341525

Adjacent sequences:  A061069 A061070 A061071 * A061073 A061074 A061075

KEYWORD

nonn

AUTHOR

Labos Elemer, May 28 2001

EXTENSIONS

More terms from David Wasserman, Jun 06 2002

STATUS

approved

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Last modified May 28 07:30 EDT 2022. Contains 354112 sequences. (Running on oeis4.)