login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A136669
Primes of the form colossally abundant number - 1.
1
5, 11, 59, 359, 5039, 55439, 1441439, 135483209545341953934626770390607999, 21406347108164028721671029721716063999, 6223083124956116561507895939157782409673929631999, 78232234099885463677928129398618807521962436643076243437332696602750813193299417065162966120702842438719999
OFFSET
1,1
COMMENTS
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.
FORMULA
{A004490(i) - 1} INTERSECTION A000040.
EXAMPLE
A004490(11) = 1441440, and 1441440 - 1 = 1441439 is prime.
CROSSREFS
KEYWORD
nonn
AUTHOR
Jonathan Vos Post, Jan 31 2011
EXTENSIONS
a(11) from Charles R Greathouse IV, Oct 09 2011
STATUS
approved