The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A156157 a(n) = 6*a(n-1)-a(n-2) for n > 2; a(1) = 17, a(2) = 85. 4
 17, 85, 493, 2873, 16745, 97597, 568837, 3315425, 19323713, 112626853, 656437405, 3825997577, 22299548057, 129971290765, 757528196533, 4415197888433, 25733659134065, 149986756915957, 874186882361677, 5095134537254105 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS lim_{n -> infinity} a(n)/a(n-1) = 3+2*sqrt(2). LINKS FORMULA a(n) = ((2+sqrt(2))*(3-2*sqrt(2))^n+(2-sqrt(2))*(3+2*sqrt(2))^n)*17/4. G.f.: 17*x*(1-x)/(1-6*x+x^2). PROG (PARI) {m=20; v=concat([17, 85], vector(m-2)); for(n=3, m, v[n]=6*v[n-1]-v[n-2]); v} CROSSREFS Second trisection of A155923. Equals 17*A001653. Cf. A156035 (decimal expansion of 3+2*sqrt(2)), A156156, A156158. Sequence in context: A156968 A212487 A288420 * A146389 A328010 A041554 Adjacent sequences:  A156154 A156155 A156156 * A156158 A156159 A156160 KEYWORD nonn AUTHOR Klaus Brockhaus, Feb 09 2009 EXTENSIONS Replaced abbreviation by sqrt(2) Klaus Brockhaus, Feb 12 2009 G.f. corrected by Klaus Brockhaus, Sep 23 2009 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 1 10:37 EDT 2021. Contains 346385 sequences. (Running on oeis4.)