This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A014642 Even octagonal numbers: 4*n*(3*n-1). 15
 0, 8, 40, 96, 176, 280, 408, 560, 736, 936, 1160, 1408, 1680, 1976, 2296, 2640, 3008, 3400, 3816, 4256, 4720, 5208, 5720, 6256, 6816, 7400, 8008, 8640, 9296, 9976, 10680, 11408, 12160, 12936, 13736, 14560, 15408, 16280, 17176, 18096, 19040, 20008, 21000, 22016 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS 8 times pentagonal numbers. - Omar E. Pol, Dec 11 2008 Sequence found by reading the line from 0, in the direction 0, 8, ..., in the square spiral whose vertices are the generalized octagonal A001082. - Omar E. Pol, Jul 18 2012 LINKS G. C. Greubel, Table of n, a(n) for n = 0..1000 Index entries for linear recurrences with constant coefficients, signature (3,-3,1). FORMULA a(n) = A000326(n)*8. - Omar E. Pol, Dec 11 2008 a(n) = A049450(n)*4 = A033579(n)*2. - Omar E. Pol, Dec 13 2008 a(n) = a(n-1) + 24*n - 16 (with a(0)=0). - Vincenzo Librandi, Nov 20 2010 G.f.: x*(8+16*x)/(1-3*x+3*x^2-x^3). - Colin Barker, Jan 06 2012 a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3). - G. C. Greubel, Jun 07 2017 MATHEMATICA s=0; lst={s}; Do[s+=n++ +8; AppendTo[lst, s], {n, 0, 8!, 24}]; lst (* Vladimir Joseph Stephan Orlovsky, Nov 16 2008 *) LinearRecurrence[{3, -3, 1}, {0, 8, 40}, 50] (* G. C. Greubel, Jun 07 2017 *) PROG (PARI) for(n=0, 25, print1(4*n*(3*n-1), ", ")) \\ G. C. Greubel, Jun 07 2017 CROSSREFS Cf. A000567, A014641, A014793, A014794, A033579, A000326, A049450. Sequence in context: A226904 A305075 A069083 * A211631 A279273 A143943 Adjacent sequences:  A014639 A014640 A014641 * A014643 A014644 A014645 KEYWORD nonn,easy,changed AUTHOR EXTENSIONS More terms from Patrick De Geest 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 January 21 09:24 EST 2019. Contains 319351 sequences. (Running on oeis4.)