This site is supported by donations to The OEIS Foundation.

 Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS". Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A198080 a(n)=(3^(3n+3)- 26n - 27)/169. 1
 0, 4, 116, 3144, 84904, 2292428, 61895580, 1671180688, 45121878608, 1218290722452, 32893849506244, 888133936668632, 23979616290053112, 647449639831434076, 17481140275448720108, 471990787437115442976, 12743751260802116960416, 344081284041657157931300 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Second differences are four times the entries of A009971. - R. J. Mathar, Oct 25 2011 LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..700 Index entries for linear recurrences with constant coefficients, signature (29,-55,27). FORMULA a(n) = (3^(3*n+3) - 26*n - 27)/169. G.f. -4*x / ( (27*x-1)*(x-1)^2 ). - R. J. Mathar, Oct 25 2011 EXAMPLE a(1) = (3^(3+3)-26-27)/169=676/169 = 4. MAPLE for n from 0 to 30 do:x:=(3^(3*n+3) - 26*n - 27)/169  :  printf(`%d, `, x):od: MATHEMATICA LinearRecurrence[{29, -55, 27}, {0, 4, 116}, 50] (* Vincenzo Librandi, Nov 25 2011 *) PROG (MAGMA) I:=[0, 4, 116]; [n le 3 select I[n] else 29*Self(n-1)-55*Self(n-2)+27*Self(n-3): n in [1..20]]; // Vincenzo Librandi, Nov 25 2011 (PARI) a(n)=(3^(3*n+3)-26*n-27)/169 \\ Charles R Greathouse IV, Jul 06 2017 CROSSREFS Sequence in context: A261457 A080482 A206689 * A272158 A194535 A030255 Adjacent sequences:  A198077 A198078 A198079 * A198081 A198082 A198083 KEYWORD nonn,easy AUTHOR Michel Lagneau, Oct 24 2011 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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.