Search: id:A003423 Results 1-1 of 1 results found. %I A003423 M4215 %S A003423 6,34,1154,1331714,1773462177794,3145168096065837266706434, %T A003423 9892082352510403757550172975146702122837936996354 %N A003423 a(n) = a(n-1)^2 - 2. %D A003423 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %D A003423 E. Lucas, "Th\'eorie des Fonctions Num\'eriques Simplement P\'eriodiques, II", Amer. J. Math., 1 (1878), 289-321. %D A003423 L. E. Dickson, History of the Theory of Numbers. Carnegie Institute Public. 256, Washington, DC, Vol. 1, 1919; Vol. 2, 1920; Vol. 3, 1923, see vol. 1, p. 376. %D A003423 J. O. Shallit, An interesting continued fraction, Math. Mag., 48 (1975), 207-211. %F A003423 a(n)=ceiling(c^(2^n)) where c=3+2*sqrt(2) is the largest root of x^2-6x+1=0. - Benoit Cloitre, Dec 03, 2002 %F A003423 a(n)=(3+sqrt(8))^(2^n)+(3-sqrt(8))^(2^n). Sum_{n>=0} 1/( prod_{k=0..n} a(k) ) = 3-sqrt(8). - Paul D. Hanna (pauldhanna(AT)juno.com), Aug 11 2004 %F A003423 a(n)=2*A001601(n+1). %F A003423 a(n-1)=Round[(1 + Sqrt[2])^(2^n)] [From Artur Jasinski (grafix(AT)csl.pl), Sep 25 2008] %t A003423 a[1] := 6; a[n_] := a[n - 1]^2 - 2; Table[a[n], {n, 1, 8}] - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Apr 11 2006 %t A003423 Table[Round[(1 + Sqrt[2])^(2^n)], {n, 1, 7}] [From Artur Jasinski (grafix(AT)csl.pl), Sep 25 2008] %o A003423 (PARI) a(n)=if(n<1, 6*(n==0), a(n-1)^2-2) %Y A003423 Cf. A001566 (starting with 3), A003010 (starting with 4), A003487 (starting with 5) %Y A003423 Sequence in context: A062819 A092336 A161323 this_sequence A145000 A046025 A009583 %Y A003423 Adjacent sequences: A003420 A003421 A003422 this_sequence A003424 A003425 A003426 %K A003423 nonn,easy %O A003423 0,1 %A A003423 N. J. A. Sloane (njas(AT)research.att.com). Search completed in 0.001 seconds