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 A133049 Squares of Mersenne primes A000668(n). 3
 9, 49, 961, 16129, 67092481, 17179607041, 274876858369, 4611686014132420609, 5316911983139663487003542222693990401, 383123885216472214589586755549637256619304505646776321 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Sum of last A000043(n) divisors of the n-th even perfect number. In other words; sum of divisors that are not powers of 2 of the n-th even perfect number, or sum of divisors that are multiples of the n-th Mersenne prime A000668(n) of the n-th even perfect number. See A139247 for more information. See the structure of the divisors of perfect numbers in A135652, A135653, A135654 and A135655. LINKS FORMULA a(n) = A000668(n)^2 EXAMPLE a(3)=961 because the 3rd Mersenne prime is 31 and 31^2=961. CROSSREFS Cf. A000290, A001248. Mersenne primes: A000668. Cf. A000043, A000396, A135652, A135653, A135654, A135655, A138247. Sequence in context: A069666 A175734 A174744 * A188140 A050632 A050638 Adjacent sequences:  A133046 A133047 A133048 * A133050 A133051 A133052 KEYWORD nonn AUTHOR Omar E. Pol, Oct 30 2007, Apr 23 2008 EXTENSIONS More terms from Olaf Voss (richyfourtythree(AT)yahoo.com), Feb 13 2008 STATUS approved

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