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A175209 Numbers n such that bigomega(bigomega(n)) ^ bigomega(n) = n. 0
1, 16, 64, 512, 1024, 6561, 16384, 32768, 531441, 2097152, 4194304, 33554432, 67108864, 387420489, 3486784401, 8589934592, 17179869184, 34359738368, 274877906944, 549755813888, 7625597484987, 22876792454961, 70368744177664 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

bigomega(.) = A001222(.).

There exists an infinity of solutions n of the form n = q^p, where q is prime, bigomega(q^p)= p, and bigomega(p)= q, if we select, for example, p = 2^q.

The first solution with q=5 is n=5^32, the first solution with q=7 is n=7^128.

LINKS

Table of n, a(n) for n=1..23.

EXAMPLE

With n = 16 = 2^4, bigomega(16)= 4, bigomega(4)= 2,and 2^4 = 16.

With n = 531441=3^12, bigomega(3^12)= 12, bigomega(12)= 3,and 3^12 = 531441.

MAPLE

with(numtheory): for n from 1 to 1000000000 do: if bigomega(bigomega(n))^bigomega(n)= n then print(n) : fi: od :

CROSSREFS

Cf. A001222, A167746.

Sequence in context: A061449 A168091 A181208 * A141840 A203281 A255576

Adjacent sequences:  A175206 A175207 A175208 * A175210 A175211 A175212

KEYWORD

nonn

AUTHOR

Michel Lagneau, Mar 05 2010

EXTENSIONS

Unspecific references and unrelated cross-references removed - R. J. Mathar, Mar 21 2010

STATUS

approved

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Last modified February 27 06:36 EST 2020. Contains 332299 sequences. (Running on oeis4.)