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A188290 Positions of 0 in the zero-one sequence [nr+4r]-[nr]-[4r], where r=sqrt(5) and []=floor. 1
17, 34, 51, 68, 89, 106, 123, 140, 161, 178, 195, 212, 233, 250, 267, 284, 305, 322, 339, 356, 373, 394, 411, 428, 445, 466, 483, 500, 517, 538, 555, 572, 589, 610, 627, 644, 661, 678, 699, 716, 733, 750, 771, 788, 805, 822, 843, 860, 877, 894, 915, 932, 949, 966, 983, 1004, 1021, 1038, 1055 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

See A187950.

LINKS

Chai Wah Wu, Table of n, a(n) for n = 1..10000

MAPLE

r := sqrt(5) ;

for n from 1 to 1200 do

        a := floor((n+4)*r)-floor(n*r)-floor(4*r) ;

        if a = 0 then

                printf("%d, ", n);

        end if;

end do: # R. J. Mathar, Jun 03 2011

MATHEMATICA

Flatten[Position[Table[Floor[(n+4)Sqrt[5]]-Floor[n*Sqrt[5]]-Floor[ 4*Sqrt[5]], {n, 1100}], 0]] (* Harvey P. Dale, Sep 23 2014 *)

PROG

(Python)

from gmpy2 import isqrt

A188290_list = [n for n in range(1, 10**6) if isqrt(5*(n+4)**2) - isqrt(5*n**2) == 8] # Chai Wah Wu, Oct 08 2016

CROSSREFS

Cf. A187950.

Sequence in context: A044842 A033014 A070814 * A268287 A249988 A098365

Adjacent sequences:  A188287 A188288 A188289 * A188291 A188292 A188293

KEYWORD

nonn,easy,changed

AUTHOR

Clark Kimberling, Mar 26 2011

EXTENSIONS

All values corrected by R. J. Mathar, Jun 03 2011

STATUS

approved

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Last modified February 20 14:52 EST 2019. Contains 320327 sequences. (Running on oeis4.)