%I A155988
%S A155988 1,27,405,5103,59049,649539,6908733,71744535,731794257,7360989291,
%T A155988 73222472421,721764371007,7060738412025,68630377364883,663426981193869,
%U A155988 6382625094934119,61149666232110753,583701359488329915
%N A155988 (2n+1)9^n
%C A155988 Sum(n>=0,1/a(n))=(3/2)log(2)
%H A155988 David H. Bailey, <a href="http://crd.lbl.gov/~dhbailey/dhbpapers/bbp-formulas.pdf">
               A Compendium of BBP-Type Formulas for Mathematical Constants</a>, 
               page 14. [From Jaume Oliver Lafont (joliverlafont(AT)gmail.com), 
               Sep 25 2009]
%H A155988 X. Gourdon and P. Sebah, <a href="http://numbers.computation.free.fr/
               Constants/Log2/log2Formulas.html">Collection of formulae for log 
               2</a>
%F A155988 G.f.: (1+9x)/(1-9x)^2
%F A155988 Linear recurrence: a(0)=1, a(1)=27, a(n)=18a(n-1)-81a(n-2) for n>=2
%o A155988 (PARI) a(n)=(2*n+1)*9^n;
%Y A155988 a(n)=A005408(n)*A001019(n). Cf. A096949, A096950, A058962 (2n+1)4^n.
%Y A155988 Cf. A154920, A164985, A165132. [From Jaume Oliver Lafont (joliverlafont(AT)gmail.com), 
               Sep 25 2009]
%Y A155988 Sequence in context: A125462 A036222 A022655 this_sequence A096950 A125484 
               A022751
%Y A155988 Adjacent sequences: A155985 A155986 A155987 this_sequence A155989 A155990 
               A155991
%K A155988 nonn
%O A155988 0,2
%A A155988 Jaume Oliver Lafont (joliverlafont(AT)gmail.com), Feb 01 2009