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Primes of the form colossally abundant number - 1.
1

%I #15 May 13 2013 01:48:46

%S 5,11,59,359,5039,55439,1441439,135483209545341953934626770390607999,

%T 21406347108164028721671029721716063999,

%U 6223083124956116561507895939157782409673929631999,78232234099885463677928129398618807521962436643076243437332696602750813193299417065162966120702842438719999

%N Primes of the form colossally abundant number - 1.

%C The n-th colossally abundant number - 1 is prime for n = 2, 3, 4, 6, 8, 9, 11, 34, 36, 43, 73, 81, 86, 115.

%F {A004490(i) - 1} INTERSECTION A000040.

%e A004490(11) = 1441440, and 1441440 - 1 = 1441439 is prime.

%Y Cf. A000040, A004490, A181561, A181562.

%K nonn

%O 1,1

%A _Jonathan Vos Post_, Jan 31 2011

%E a(11) from _Charles R Greathouse IV_, Oct 09 2011