A136324 Interleaving of A002450(n), A002450(n) + 1.

0, 1, 1, 2, 5, 6, 21, 22, 85, 86, 341, 342, 1365, 1366, 5461, 5462, 21845, 21846, 87381, 87382, 349525, 349526, 1398101, 1398102, 5592405, 5592406, 22369621, 22369622, 89478485, 89478486, 357913941

Offset: 0

Author

Paul Curtz, Mar 26 2008

Keywords

• nonn

Links

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

Programs

Magma

[1/6 - (1/2)*(-1)^n + (1/4)*2^n + (1/12)*(-2)^n: n in [0..40]]; // Vincenzo Librandi, Aug 09 2011

Formula

a(n) = 5*a(n-2) - 4*a(n-4).

From Lambert Herrgesell (zero815(AT)googlemail.com), Apr 19 2008: (Start)

a(n) = 1/6 - (1/2)*(-1)^n + (1/4)*2^n + (1/12)*(-2)^n;

g.f.: (-3*x^3 + x^2 + x)/(4*x^4 - 5*x^2 + 1). (End)

Extensions

More terms from Lambert Herrgesell (zero815(AT)googlemail.com), Apr 19 2008