A171470 a(n) = 6*a(n-1) - 8*a(n-2) for n > 2; a(0) = 11, a(1) = 90, a(2) = 372.

11, 90, 372, 1512, 6096, 24480, 98112, 392832, 1572096, 6289920, 25162752, 100657152, 402640896, 1610588160, 6442401792, 25769705472, 103079018496, 412316467200, 1649266655232, 6597068193792, 26388275920896

Offset: 0

Author

Klaus Brockhaus, Dec 09 2009

Keywords

• nonn
• easy

Comments

Related to Reverse and Add trajectory of 22 in base 2: A061561(4*n) = 2*a(n).

Binary representation of a(n) for n > 0 is given by the following production rules of the contextfree grammar: S -> 101 T 0, T -> 1 T 0 | 101. - A.H.M. Smeets, Feb 11 2019

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..500
• Index entries for linear recurrences with constant coefficients, signature (6,-8).

Crossrefs

Cf. A061561, A171471, A171472, A171473.

Programs

PARI

{m=21; v=concat([11, 90, 372], vector(m-3)); for(n=4, m, v[n]=6*v[n-1]-8*v[n-2]); v}

Formula

a(n) = 24*4^n-3*2^n for n > 0.

G.f.: (1+4*x)*(11-20*x)/((1-2*x)*(1-4*x)).