A202337 Range of A062723.

1, 2, 6, 12, 36, 108, 324, 972, 2916, 8748, 26244, 78732, 236196, 708588, 2125764, 6377292, 19131876, 57395628, 172186884, 516560652, 1549681956, 4649045868, 13947137604, 41841412812, 125524238436, 376572715308, 1129718145924, 3389154437772, 10167463313316

Offset

1,2

Comments

Subsequence of A000792.

Apparently a(n) = A052156(n - 1) for n >= 4. - Georg Fischer, Mar 26 2019

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

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

Formula

From Colin Barker, Mar 26 2019: (Start)

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

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

a(n) = 3*a(n-1) for n>4.

(End)

Prog

(Haskell)
a202337 n = a202337_list !! (n-1)
a202337_list = f a062723_list where
   f (x:xs'@(x':xs)) = if x == x' then f xs' else x : f xs'

Crossrefs

Cf. A000792, A003946, A027327, A025579, A052156, A062723.

Sequence in context: A026549 A120766 A121404 * A189854 A189565 A074442

Adjacent sequences: A202334 A202335 A202336 * A202338 A202339 A202340

Keyword

nonn

Author

Reinhard Zumkeller, Dec 17 2011

Status

approved