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A181555 a(n)=A002110(n)^n. 8
1, 2, 36, 27000, 1944810000, 65774855015100000, 733384949590939374729000000, 9037114296609938214167920266348510000000, 78354300210436852307898467208663359164858967744100000000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

For n>0, a(n)= first counting number whose prime signature consists of n repeated n times (cf. A002024). Subsequence of A025487.

LINKS

Table of n, a(n) for n=0..8.

EXAMPLE

a(4) = 1944810000 = 210^4 = 2^4 * 3^4 * 5^4 * 7^4.

CROSSREFS

A061742(n) = A002110(n)^2. See also A006939, A066120, A166475, A167448.

A000005(a(n)) = A000169(n). The divisors of a(n) appear as the first A000169(n) terms of A178479, with A178479(A000169(n)) = a(n).

A071207(n, k) gives the number of divisors of n with (n-k) distinct prime factors, A181567(n, k) gives the number of divisors of n with k prime factors counted with multiplicity. Cf. A001221, A001222, A146290, A146292.

Sequence in context: A134366 A265944 A127234 * A283261 A280420 A051459

Adjacent sequences:  A181552 A181553 A181554 * A181556 A181557 A181558

KEYWORD

easy,nonn

AUTHOR

Matthew Vandermast, Oct 31 2010

STATUS

approved

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Last modified May 27 13:22 EDT 2017. Contains 287205 sequences.