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A155803 A023001 interleaved with 2*A023001 and 4*A023001. 2
0, 0, 0, 1, 2, 4, 9, 18, 36, 73, 146, 292, 585, 1170, 2340, 4681, 9362, 18724, 37449, 74898, 149796, 299593, 599186, 1198372, 2396745, 4793490, 9586980, 19173961, 38347922, 76695844, 153391689, 306783378, 613566756, 1227133513, 2454267026, 4908534052 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

A033138 with three zeros prepended. - Joerg Arndt, Mar 10 2015

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (2,0,1,-2).

FORMULA

a(3n)= A023001(n). a(3n+1)=2*A023301(n) = A125835(n). a(3n+2) = 4*A023001(n).

a(n)= a(n-3)+2^(n-3) = a(n-3)+A000079(n-3). Here, a(.) can also be one of its higher order differences.

a(n)= 2*a(n-1)+a(n-3)-2*a(n-4). G.f.: x^3/((x-1)*(2*x-1)*(1+x+x^2)). [R. J. Mathar, Jul 23 2009]

a(n)=floor(2^n/7) [Mircea Merca, Dec 22 2010]

MAPLE

A023001 := proc(n) (8^n-1)/7; end: A155803 := proc(n) RETURN( A023001(n), 2*A023001(n), 4*A023001(n)) ; end: L := [seq(A155803(n), n=0..30)] ; # R. J. Mathar, Jul 23 2009

seq(floor(2^n/7), n=0..30) # Mircea Merca, Dec 22 2010

MATHEMATICA

CoefficientList[Series[x^3/(1-2 x-x^3+2 x^4), {x, 0, 50}], x]  (* Harvey P. Dale, Mar 13 2011 *)

PROG

(MAGMA) [Floor(2^n/7): n in [0..40]]; // Vincenzo Librandi, Sep 17 2011

CROSSREFS

Sequence in context: A119027 A145139 A033138 * A293352 A293327 A282909

Adjacent sequences:  A155800 A155801 A155802 * A155804 A155805 A155806

KEYWORD

nonn,easy

AUTHOR

Paul Curtz, Jan 27 2009

EXTENSIONS

Edited and extended by R. J. Mathar, Jul 23 2009

STATUS

approved

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Last modified February 24 03:22 EST 2020. Contains 332195 sequences. (Running on oeis4.)