A109217 - OEIS

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.

0, 0, 1, 11, 110, 1101, 11011, 110111, 1101111, 11011110, 110111101, 1101111011, 11011110111, 110111101111, 1101111011111, 11011110111111, 110111101111110, 1101111011111101, 11011110111111011, 110111101111110111, 1101111011111101111, 11011110111111011111

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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