A258439 Powers of 3 alternating with powers of 2.

1, 1, 3, 2, 9, 4, 27, 8, 81, 16, 243, 32, 729, 64, 2187, 128, 6561, 256, 19683, 512, 59049, 1024, 177147, 2048, 531441, 4096, 1594323, 8192, 4782969, 16384, 14348907, 32768, 43046721, 65536, 129140163, 131072, 387420489, 262144, 1162261467

Offset

0,3

Comments

a(n)*A098293(n) = A000400(floor(n/2)).

Links

Colin Barker, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (0,5,0,-6).

Formula

a(n) = ((5+(-1)^n)/2)^((2*n-1+(-1)^n)/4).

a(n) = 5*a(n-2)-6*a(n-4). - Colin Barker, May 30 2015

G.f.: -(3*x^3+2*x^2-x-1) / ((2*x^2-1)*(3*x^2-1)). - Colin Barker, May 30 2015

Maple

seq(op([3^n, 2^n]), n=0..20); # Muniru A Asiru, Jul 16 2018

Mathematica

Flatten[Table[{3^n, 2^n}, {n, 0, 25}]] (* Vincenzo Librandi, Jul 17 2018

Prog

(PARI) Vec(-(3*x^3+2*x^2-x-1)/((2*x^2-1)*(3*x^2-1)) + O(x^100)) \\ Colin Barker, May 30 2015
(GAP) Flat(List([0..20], n->[3^n, 2^n])); # Muniru A Asiru, Jul 16 2018
(Magma) &cat[[3^n, 2^n]: n in [0..35]]; // Vincenzo Librandi, Jul 17 2018

Crossrefs

Cf. A098293, A006899.

Sequence in context: A347365 A251555 A090880 * A346105 A188926 A193980

Adjacent sequences: A258436 A258437 A258438 * A258440 A258441 A258442

Keyword

nonn,easy

Author

Luce ETIENNE, May 30 2015

Status

approved