A365807 a(n) = 1 if A163511(n) is a square, 0 otherwise.

1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1

Offset

0

Links

Antti Karttunen, Table of n, a(n) for n = 0..65537

Index entries for sequences related to binary expansion of n

Index entries for characteristic functions

Formula

a(0) = 1, a(1) = 0, a(2) = 1; for n > 2, if n is odd, then a(n) = a((n-1)/2), and if n is a multiple of 4, then a(n) = a(n/4), otherwise a(n) = 0.

a(n) = A010052(A163511(n)).

a(n) = A059841(A365805(n)).

Prog

(PARI)
A163511(n) = if(!n, 1, my(p=2, t=1); while(n>1, if(!(n%2), (t*=p), p=nextprime(1+p)); n >>= 1); (t*p));
A365807(n) = issquare(A163511(n));
(PARI) A365807(n) = if(n<=2, !(n%2), if(n%2, A365807((n-1)/2), if(n%4, 0, A365807(n/4))));

Crossrefs

Characteristic function of A365808.

Cf. A010052, A059841, A163511, A365805.

Sequence in context: A243148 A089495 A345703 * A173857 A114482 A371844

Adjacent sequences: A365804 A365805 A365806 * A365808 A365809 A365810

Keyword

nonn

Author

Antti Karttunen, Oct 01 2023

Status

approved