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A109217 a(n) is the binary string of length n+1 that has 0's at indices that are squares and 1's elsewhere, where the most significant digit has index 0. 2
0, 0, 1, 11, 110, 1101, 11011, 110111, 1101111, 11011110, 110111101, 1101111011, 11011110111, 110111101111, 1101111011111, 11011110111111, 110111101111110, 1101111011111101, 11011110111111011, 110111101111110111, 1101111011111101111, 11011110111111011111 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Michael De Vlieger, Table of n, a(n) for n = 0..1001

EXAMPLE

110111101 is a term because the string '00110111101' has zeros at the square indices 0,1,4,9 and the first two zeros are dropped.

MATHEMATICA

With[{s = Array[Boole[! IntegerQ@ Sqrt@ #] &, 1002, 0]}, Array[FromDigits[s[[1 ;; #]] ] &, Length@ s]] (* Michael De Vlieger, Mar 23 2020 *)

PROG

(PARI) a(n) = fromdigits(vector(n, i, !issquare(i))); \\ Jinyuan Wang, Mar 22 2020

CROSSREFS

Cf. A000037, A049240, A109218.

Sequence in context: A065829 A261299 A081933 * A266680 A320890 A036843

Adjacent sequences:  A109214 A109215 A109216 * A109218 A109219 A109220

KEYWORD

nonn,base,easy

AUTHOR

Jason Earls, Jun 22 2005

EXTENSIONS

Name changed, several terms inserted, and one more term from Jinyuan Wang, Mar 22 2020

STATUS

approved

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Last modified September 19 00:22 EDT 2021. Contains 347549 sequences. (Running on oeis4.)