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A072260 ((6n+19)*4^n-1)/3. 5
6, 33, 165, 789, 3669, 16725, 75093, 333141, 1463637, 6378837, 27612501, 118838613, 508908885, 2169853269, 9216283989, 39012619605, 164640413013, 692921390421, 2909124515157 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Related to Collatz function (for n>0). All divisible by 3.

LINKS

Table of n, a(n) for n=0..18.

Index entries for linear recurrences with constant coefficients, signature (9,-24,16).

FORMULA

G.f.: 3*(2-7*x+4*x^2)/((1-x)*(1-4*x)^2). - Bruno Berselli, Dec 16 2011

PROG

(PARI) a(n)=((6*n+19)*4^n-1)/3 \\ Charles R Greathouse IV, Oct 07 2015

CROSSREFS

Cf. A072257, A072258, A072259.

Sequence in context: A290921 A240880 A099432 * A281930 A282371 A291004

Adjacent sequences:  A072257 A072258 A072259 * A072261 A072262 A072263

KEYWORD

nonn,easy

AUTHOR

N. Rathankar (rathankar(AT)yahoo.com), Jul 08 2002

EXTENSIONS

Edited and extended by Henry Bottomley, Aug 06 2002

STATUS

approved

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Last modified February 25 18:49 EST 2018. Contains 299655 sequences. (Running on oeis4.)