A378449 Characteristic function of A083209: a(n) = 1 if there is exactly one subset of the divisors of n such that the complement has the same sum, otherwise 0.

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

Offset

1

Links

Antti Karttunen, Table of n, a(n) for n = 1..101632

Index entries for characteristic functions

Formula

a(n) = [A083206(n) = 1], where [ ] is the Iverson bracket.

a(n) <= A378598(n) <= A179527(n).

Prog

(PARI)
A083206(n) = { my(p=1); fordiv(n, d, p *= ('x^d + 'x^-d)); (polcoeff(p, 0)/2); };
A378449(n) = (1==A083206(n));

Crossrefs

Characteristic function of A083209.

Cf. A083206, A179527, A378448, A378598.

Sequence in context: A078926 A324824 A025458 * A286925 A378598 A378540

Adjacent sequences: A378446 A378447 A378448 * A378450 A378451 A378452

Keyword

nonn,changed

Author

Antti Karttunen, Nov 28 2024

Status

approved