A380439 a(n) = 1 if A003557(n)^2 > n, otherwise 0, where A003557(n) is n divided by its squarefree kernel.

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

Offset

1

Links

Antti Karttunen, Table of n, a(n) for n = 1..100000

Index entries for characteristic functions.

Formula

a(n) = [A003557(n)^2 > n], where [ ] is the Iverson bracket.

Maple

f:= proc(n)
   if n > convert(numtheory:-factorset(n), `*`)^2 then 1 else 0 fi
end proc:
map(f, [$1..200]); # Robert Israel, Jan 27 2025

Prog

(PARI)
A003557(n) = (n/factorback(factor(n)[, 1]));
A380439(n) = ((A003557(n)^2) > n);

Crossrefs

Characteristic function of A059172.

Cf. A003557.

Sequence in context: A382424 A187946 A330549 * A342019 A323510 A044938

Adjacent sequences: A380436 A380437 A380438 * A380440 A380441 A380442

Keyword

nonn

Author

Antti Karttunen, Jan 27 2025

Status

approved