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%I #12 Mar 20 2021 10:55:12
%S 3,14,60,248,336,4064,15120,16380,261888,1089270,11784960,16775168,
%T 22766400,71495424,229909120,689727360,738152448,4294934528,
%U 7091219520,15999197760,21930739200,25500590080,33216860160
%N Even multiply-perfect numbers divided by 2.
%C Just as no odd perfect number is known, all known multiply-perfect numbers A007691 greater than 1 are even.
%C The subsequence of even perfect numbers divided by 2 is A133028.
%C The subsequence of even triperfects / 2 is A326051. - _Antti Karttunen_, Mar 20 2021
%D R. K. Guy, Unsolved Problems in Number Theory, B2.
%F a(n) = A007691(n+1)/2.
%F a(n) = A194771(n+1)/4. [provided there are no odd multiperfect numbers > 1] - _Antti Karttunen_, Mar 20 2021
%Y Cf. A007691, A133028, A194771, A326051.
%K nonn
%O 1,1
%A _Jonathan Sondow_, Nov 22 2012