Search: id:A046176 Results 1-1 of 1 results found. %I A046176 %S A046176 1,35,1189,40391,1372105,46611179,1583407981,53789260175, %T A046176 1827251437969,62072759630771,2108646576008245,71631910824649559, %U A046176 2433376321462076761,82663163018885960315,2808114166320660573949 %N A046176 Indices of square numbers which are also hexagonal. %C A046176 Bisection (even part) of Chebyshev sequence with Diophantine property. %C A046176 (3*b(n))^2 - 2*(2*a(n+1))^2 = 1 with companion sequence b(n)=A077420(n), n>=0. %C A046176 Sequence also refers to inradius of primitive Pythagorean triangles with consecutive legs, odd followed by even. - Lekraj Beedassy (blekraj(AT)yahoo.com), Apr 23 2003 %H A046176 Tanya Khovanova, Recursive Sequences %H A046176 Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics. %H A046176 Index entries for sequences related to Chebyshev polynomials. %F A046176 a(n)=34*a(n-1)-a(n-2), a(0)=-1, a(1)=1. %F A046176 a(n+1)= S(2*n, 6)= S(n, 34) + S(n-1, 34), n>=1, with S(n, x) := U(n, x/2) Chebyshev's polynomials of the second kind. See A049310. S(n, 34)=A029547(n). %F A046176 G.f.: x*(1+x)/(1-34*x+x^2). %F A046176 a(n+1)= sum((-1)^k*binomial(2*n-k, k)*6^(2*(n-k)), k=0..n), n>=0. %F A046176 a(n)=A001109(2n+1). - Lekraj Beedassy (blekraj(AT)yahoo.com), Apr 23 2003 %F A046176 Define f[x,s] = s x + Sqrt[(s^2-1)x^2+1]; f[0,s]=0. a(n) = f[f[a(n-1), 3],3]. - Marcos Carreira, Dec 27 2006 %F A046176 (1) a(n) = (sqrt(2)/8)(3+2*sqrt(2))*(17+12*sqrt(2))^(n-1) -(sqrt(2)/8)(3-2*sqrt(2))*(17-12*sqrt(2))^(n-1) - Antonio A. Olivares (olivares14031(AT)yahoo.com), Mar 22 2008 %F A046176 (2) a(n) = (sqrt(2)/8)*(17+12*sqrt(2))^(n-1/2) -(sqrt(2)/8)*(17-12*sqrt(2))^(n-1/ 2) - Antonio A. Olivares (olivares14031(AT)yahoo.com), Mar 22 2008 %F A046176 (3) a(n) = (sqrt(2)/8)*(3+2*sqrt(2))^(2n-1) -(sqrt(2)/8)*(3-2*sqrt(2))^(2n-1) - Antonio A. Olivares (olivares14031(AT)yahoo.com), Mar 22 2008 %F A046176 (4) a(n) = (sqrt(2)/8)*(1+sqrt(2))^(4n-2) -(sqrt(2)/8)*(1-sqrt(2))^(4n-2) - Antonio A. Olivares (olivares14031(AT)yahoo.com), Mar 22 2008 %F A046176 (5) a(n) = 35*a(n-1) - 35*a(n-2) + a(n-3) - Antonio A. Olivares (olivares14031(AT)yahoo.com), Mar 22 2008 %F A046176 a(n+1)=17*a(n)+6*(8*a(n)^2+1)^0.5 for n>=0 [From Richard Choulet (richardchoulet(AT)yahoo.fr), May 01 2009] %t A046176 q=9;s=0;lst={};Do[s+=n;If[Sqrt[q*s+1]==Floor[Sqrt[q*s+1]],AppendTo[lst, Sqrt[q*s+1]]],{n,0,9!}];lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Apr 02 2009] %Y A046176 Cf. A008844, A046177. %Y A046176 Cf. A001109. %Y A046176 Sequence in context: A002453 A049395 A115492 this_sequence A029546 A126158 A095153 %Y A046176 Adjacent sequences: A046173 A046174 A046175 this_sequence A046177 A046178 A046179 %K A046176 nonn %O A046176 1,2 %A A046176 Eric Weisstein (eric(AT)weisstein.com) %E A046176 Chebyshev comments from W. Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de), Nov 29 2002 Search completed in 0.002 seconds