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Search: id:A058891
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A058891 2^(2^(n-1)-1). +0
9
1, 2, 8, 128, 32768, 2147483648, 9223372036854775808, 170141183460469231731687303715884105728, 57896044618658097711785492504343953926634992332820282019728792003956564819968 (list; graph; listen)
OFFSET

1,2

COMMENT

For n>1 a(n) is the only solution >1 to core(x)^(n-1)=tau(x) where core(x) is the square-free part of x and tau(x) the number of divisors of x. - Benoit Cloitre (benoit7848c(AT)orange.fr), Apr 18 2002

REFERENCES

F. Harary, Graph Theory, Page 209, Problem 16.11.

FORMULA

a(1)=1, a(n+1)=2*a(n)^2.

a(1)=1, a(n+1) = 2^n*a(1)*a(2)*...*a(n) - Benoit Cloitre (benoit7848c(AT)orange.fr), Sep 13 2003

CROSSREFS

Sequence in context: A114977 A011822 A111179 this_sequence A058343 A111827 A045330

Adjacent sequences: A058888 A058889 A058890 this_sequence A058892 A058893 A058894

KEYWORD

nonn,easy

AUTHOR

njas, Jan 08 2001

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Last modified September 5 19:27 EDT 2008. Contains 143485 sequences.


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