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%I #6 Mar 26 2023 09:31:21
%S 6,28,248,2032,262112,8388544,67108736,549755813632,
%T 1180591620717411302912,633825300114114700748351601664,
%U 332306998946228968225951765070084096,696898287454081973172991196020261297057792
%N Product of n-th Mersenne prime and 2^n.
%C a(1)= 6, the first perfect number. a(2)= 28, the second perfect number. a(3)=248, the dimensions of E_8.
%F a(n)=A000668(n) * 2^n.
%e a(3)=248 because the third Mersenne prime is 31, 2^3=8 and 31*8=248.
%t Table[(2^MersennePrimeExponent[n]-1)2^n,{n,12}] (* _Harvey P. Dale_, Mar 26 2023 *)
%Y Cf. A061029. Powers of 2: A000079. Mersenne primes: A000668.
%K nonn
%O 1,1
%A _Omar E. Pol_, Nov 25 2007
%E Spelling corrected and n(7) added by _Jason G. Wurtzel_, Aug 22 2010
%E More terms from _Harvey P. Dale_, Mar 26 2023
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