A154882 - OEIS

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A154882 - OEIS

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A154882

a(n) is the smallest number with at least as many divisors as a(n-1)^2.

0

2, 4, 12, 120, 7560, 8648640, 1927522396800, 4747472432036420486400, 128438082648984172330026178330296384000, 6184173455628205993842062057864303743050691444602955105860128640000

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Table of n, a(n) for n=1..10.

FORMULA

a(n) = A061799(A048691(a(n-1))). - R. J. Mathar, Jan 21 2009

EXAMPLE

4^2 = 16 has 5 divisors; the smallest number with at least 5 divisors is 12.

CROSSREFS

Sequence in context: A326969 A304986 A013333 * A062000 A053040 A154734

Adjacent sequences: A154879 A154880 A154881 * A154883 A154884 A154885

KEYWORD

nonn

AUTHOR

J. Lowell, Jan 16 2009

EXTENSIONS

a(6)-a(10) from Donovan Johnson, May 09 2009

STATUS

approved