A118263 a(3n) = 2^n, a(3n+1) = 3^n, a(3n+2) = 4^n.

1, 1, 1, 2, 3, 4, 4, 9, 16, 8, 27, 64, 16, 81, 256, 32, 243, 1024, 64, 729, 4096, 128, 2187, 16384, 256, 6561, 65536, 512, 19683, 262144, 1024, 59049, 1048576, 2048, 177147, 4194304, 4096, 531441, 16777216, 8192, 1594323, 67108864, 16384, 4782969

Offset: 0

Author

Hans Isdahl, Sep 20 2007

Keywords

• nonn
• easy

Links

• Harvey P. Dale, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (0,0,9,0,0,-26,0,0,24).

Programs

Mathematica

Table[{2^Floor[n/3], 3^Floor[n/3], 4^Floor[n/3]}[[Mod[n, 3] + 1]], {n, 0, 100}] (* Olivier Gérard, Sep 20 2007 *)
LinearRecurrence[{0,0,9,0,0,-26,0,0,24},{1,1,1,2,3,4,4,9,16},60] (* Harvey P. Dale, Jan 30 2021 *)

Formula

From R. J. Mathar, Mar 01 2010: (Start)

a(n) = 9*a(n-3) - 26*a(n-6) + 24*a(n-9).

G.f.: -(1+x+x^2-7*x^3-6*x^4-5*x^5+12*x^6+8*x^7+6*x^8) / ((3*x^3-1) * (2*x^3-1) * (4*x^3-1)). (End)

Extensions

More terms from Olivier Gérard, Sep 20 2007