A177846 a(n) = 6*a(n-1)-8*a(n-2) for n > 2; a(0)=837, a(1)=7896, a(2)=32176.

837, 7896, 32176, 129888, 521920, 2092416, 8379136, 33535488, 134179840, 536795136, 2147332096, 8589631488, 34359132160, 137437741056, 549753389056, 2199018405888, 8796083322880, 35184352690176, 140737449558016

Offset

0,1

Comments

Related to Reverse and Add trajectory of 775 in base 2: a(n) = A077077(4*n+3)/6, i.e. one sixth of fourth quadrisection of A077077.

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (6, -8).

Formula

a(n) = 2*4^(n+5)-37*2^(n+2) for n > 0.

G.f.: (837+2874*x-8504*x^2) / ((1-2*x)*(1-4*x)).

G.f. for the sequence starting at a(1): 8*x*(987-1900*x) / ((1-2*x)*(1-4*x)).

Mathematica

CoefficientList[Series[(837 + 2874 x - 8504 x^2)/((1 - 2 x) (1 - 4 x)), {x, 0, 40}], x] (* Vincenzo Librandi, Sep 24 2013 *)

Prog

(PARI) {m=19; v=concat([837, 7896, 32176], vector(m-3)); for(n=4, m, v[n]=6*v[n-1]-8*v[n-2]); v}
(Magma) [837] cat [2*4^(n+5)-37*2^(n+2): n in [1..25]]; // Vincenzo Librandi, Sep 24 2013

Crossrefs

Cf. A077077 (Reverse and Add trajectory of 775 in base 2), A177843, A177844, A177845.

Sequence in context: A357326 A322524 A016113 * A167603 A284187 A202716

Adjacent sequences: A177843 A177844 A177845 * A177847 A177848 A177849

Keyword

nonn,easy

Author

Klaus Brockhaus, May 14 2010

Status

approved