login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A037597 Base-4 digits are, in order, the first n terms of the periodic sequence with initial period 1,3,0. 2
1, 7, 28, 113, 455, 1820, 7281, 29127, 116508, 466033, 1864135, 7456540, 29826161, 119304647, 477218588, 1908874353, 7635497415, 30541989660, 122167958641, 488671834567, 1954687338268, 7818749353073, 31274997412295 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..300

Index entries for linear recurrences with constant coefficients, signature (4,0,1,-4).

FORMULA

a(n) = floor(4^(n+1)/9). [Mircea Merca, Dec 26 2010]

G.f.: x*(1+3*x) / ( (x-1)*(4*x-1)*(1+x+x^2) ). [Joerg Arndt, Jan 08 2011]

a(n) = 4*a(n-1) + a(n-3) - 4*a(n-4). [Joerg Arndt, Jan 08 2011]

a(1)=1, a(2)=7, a(n) = 5*a(n-1) - 4*a(n-2) + (period 3: repeat -3, 1, 2); a(n) = 4*a(n) +1 + (period 3: repeat 0, 1, 3). [Vincenzo Librandi, Jun 06 2011]

MAPLE

seq(floor(4^(n+1)/9), n=1..32); # Mircea Merca, Dec 28 2010

PROG

(MAGMA) [Floor(4^(n+1)/9): n in [1..30]]; // Vincenzo Librandi, May 22 2011

(PARI) a(n)=4^(n+1)\9 \\ Charles R Greathouse IV, Jun 06 2011

CROSSREFS

Cf. A178744.

Sequence in context: A002042 A200666 A207098 * A037702 A302523 A290913

Adjacent sequences:  A037594 A037595 A037596 * A037598 A037599 A037600

KEYWORD

nonn,base,easy

AUTHOR

Clark Kimberling

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 31 02:33 EDT 2021. Contains 346367 sequences. (Running on oeis4.)