A085010 a(n)=2^(2^n)*sum(k=0,n,1/2^(2^k)).

1, 3, 13, 209, 53505, 3506503681, 15060318633198616577, 277813843495134114797235287762174738433, 94535152227927400227782074307303551040545228366095741656402842333161034088449

Offset: 0

Author

Benoit Cloitre, Jun 19 2003

Keywords

• nonn

Crossrefs

Cf. A007404.

Formula

a(n)=A074854(2^n)=; a(n)=floor(c*2^(2^n)) where c=sum(k>=0, 1/2^(2^k))=0.81642150902...

a(n + 1) = 1 + a(n)*2^(2^n), a(0) = 1 [From Peter Moxey (pmoxey(AT)live.com), Mar 14 2010]