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A166450 a(n) = 3*a(n-2) for n > 2; a(1) = 1, a(2) = 6. 1
1, 6, 3, 18, 9, 54, 27, 162, 81, 486, 243, 1458, 729, 4374, 2187, 13122, 6561, 39366, 19683, 118098, 59049, 354294, 177147, 1062882, 531441, 3188646, 1594323, 9565938, 4782969, 28697814, 14348907, 86093442, 43046721, 258280326 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Interleaving of A000244 and 6*A000244.

Second binomial transform is A055845. Sixth binomial transform is A153597.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (0,3).

FORMULA

a(n) = (3+(-1)^n)*3^(1/4*(2*n-1+(-1)^n))/2.

G.f.: x*(1+6*x)/(1-3*x^2).

MATHEMATICA

LinearRecurrence[{0, 3}, {1, 6}, 50] (* G. C. Greubel, May 14 2016 *)

PROG

(MAGMA) [ n le 2 select 5*n-4 else 3*Self(n-2): n in [1..35] ];

CROSSREFS

Cf. A000244 (powers of 3), A055845, A153597.

Sequence in context: A067990 A174012 A050008 * A019069 A213752 A134410

Adjacent sequences:  A166447 A166448 A166449 * A166451 A166452 A166453

KEYWORD

nonn,easy

AUTHOR

Klaus Brockhaus, Oct 13 2009

STATUS

approved

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Last modified April 21 04:39 EDT 2021. Contains 343146 sequences. (Running on oeis4.)