Search: id:A059918 Results 1-1 of 1 results found. %I A059918 %S A059918 1,4,40,3280,21523360,926510094425920,1716841910146256242328924544640, %T A059918 5895092288869291585760436430706259332839105796137920554548480 %N A059918 a(n) = (3^(2^n)-1)/2. %C A059918 Denominator of b(n) where b(n) = 1/2*(b(n-1) + 1/b(n-1)), b(0)=2. - Vladeta Jovovic (vladeta(AT)eunet.rs), Aug 15 2002 %H A059918 Harry J. Smith, Table of n, a(n) for n=0,...,11 %F A059918 a(n) = a(n-1)*(3^(2^(n-1))+1) with a(0) = 1. %F A059918 a(n) = (3^(2^n)-1)/2 = (A059723(n+1)-A059723(n))/A059723(n) = A059917(n)-1 = a(n-1)*A059919(n-1) = a(n-1)*(A011764(n-1)+1) %F A059918 1 = Sum(0, inf.) 3^(2^n)/a(n+1). 1 = 3/4 + 9/40 + 81/3280 + 6561/21523360 + ...; with partial sums: 3/4, 39/40, 3279/3280, 21523359/21523360...[a(n)-1]/ a(n)...==> 1. - Gary W. Adamson (qntmpkt(AT)yahoo.com), Jun 22 2003 %o A059918 (PARI) { for (n=0, 11, write("b059918.txt", n, " ", (3^(2^n) - 1)/2); ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Jun 30 2009] %Y A059918 Cf. A059917. %Y A059918 Sequence in context: A139688 A072445 A000841 this_sequence A002677 A119527 A074991 %Y A059918 Adjacent sequences: A059915 A059916 A059917 this_sequence A059919 A059920 A059921 %K A059918 nonn,frac %O A059918 0,2 %A A059918 Henry Bottomley (se16(AT)btinternet.com), Feb 08 2001 Search completed in 0.001 seconds