A005015 a(n) = 11*2^n.

11, 22, 44, 88, 176, 352, 704, 1408, 2816, 5632, 11264, 22528, 45056, 90112, 180224, 360448, 720896, 1441792, 2883584, 5767168, 11534336, 23068672, 46137344, 92274688, 184549376, 369098752, 738197504, 1476395008, 2952790016, 5905580032, 11811160064

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Comments

The first differences are the sequence itself. - Alexandre Wajnberg & Eric Angelini, Sep 07 2005

11 times powers of 2. - Omar E. Pol, Dec 16 2008

A144472 = -1,2,9,13,31,57,.... a(n) = A144472(n+1)+A144472(n+2). Also a(n) = A144472(n+3)-A144472(n+1). A144472(n+1) is a Jacobsthal sequence from 2 and 9: A144472(n+3) = A144472(n+2)+2*A144472(n+1). Note a(n) mod 9 = period 6: repeat 2,4,8,7,5,1 = A153130(n+1). - Paul Curtz, Jan 06 2009

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..1000
• Tanya Khovanova, Recursive Sequences
• Index entries for linear recurrences with constant coefficients, signature (2).

Crossrefs

Row sums of (10, 1)-Pascal triangle A093645.

Cf. A000079, A144472, A153130.

Programs

Magma

[11*2^n: n in [0..40]]; // Vincenzo Librandi, Aug 14 2011

Mathematica

11*2^Range[0, 60] (* Vladimir Joseph Stephan Orlovsky, Jun 09 2011 *)
NestList[2#&,11,30] (* Harvey P. Dale, Jun 11 2021 *)

PARI

a(n)=11<Charles R Greathouse IV, Oct 07 2015

Formula

G.f.: 11/(1-2*x).

a(n) = 2*a(n-1), n>0; a(0)=11. - Philippe Deléham, Nov 23 2008

a(n) = A000079(n)*11. - Omar E. Pol, Dec 16 2008

E.g.f.: 11*exp(2*x). - Elmo R. Oliveira, Aug 16 2024