This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A173873 a(n) = 2*a(n-1) + 13, a(1)=1. 1
 1, 15, 43, 99, 211, 435, 883, 1779, 3571, 7155, 14323, 28659, 57331, 114675, 229363, 458739, 917491, 1834995, 3670003, 7340019, 14680051, 29360115, 58720243, 117440499, 234881011, 469762035, 939524083, 1879048179, 3758096371 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Prime numbers in this sequence are (43, 211, 883, 3571, 14323, 57331, 234881011, 3758096371, 3848290697203, ... ) LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..1000 Index entries for linear recurrences with constant coefficients, signature (3,-2). FORMULA a(n) = 3*a(n-1) - 2*a(n-2). - Vincenzo Librandi_, Jul 15 2012 G.f.: x*(1+12*x)/(1 - 3*x + 2*x^2). - Vincenzo Librandi, Jul 15 2012 EXAMPLE a(2) = 2*1  + 13 = 15; a(3) = 2*15 + 13 = 43; a(4) = 2*43 + 13 = 99. MATHEMATICA RecurrenceTable[{a[1]==1, a[n]==2*a[n-1]+13}, a, {n, 40}] (* Vincenzo Librandi, Jul 15 2012 *) LinearRecurrence[{3, -2}, {1, 15}, 30] (* Harvey P. Dale, Aug 26 2019 *) PROG (MAGMA) I:=[1]; [n le 1 select I[n] else 2*Self(n-1)+13: n in [1..30]]; // Vincenzo Librandi, Jul 15 2012 CROSSREFS Sequence in context: A072119 A069127 A137183 * A124708 A204734 A126369 Adjacent sequences:  A173870 A173871 A173872 * A173874 A173875 A173876 KEYWORD nonn,easy AUTHOR Vincenzo Librandi, Mar 06 2010 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 December 7 18:12 EST 2019. Contains 329847 sequences. (Running on oeis4.)