A378448 Characteristic function of A064771: a(n) = 1 if there is exactly one subset of the proper divisors of n that sum to n, otherwise 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, 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, 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, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0

Offset

1

Links

Antti Karttunen, Table of n, a(n) for n = 1..108045

Index entries for characteristic functions

Formula

a(n) = [A065205(n) = 1], where [ ] is the Iverson bracket.

Prog

(PARI)
A033630(n) = if(!n, 1, my(p=1); fordiv(n, d, p *= (1 + 'x^d)); polcoeff(p, n));
A378448(n) = (2==A033630(n));

Crossrefs

Characteristic function of A064771.

Cf. A033630, A065205, A065235, A378449.

Sequence in context: A318880 A177063 A378529 * A341619 A378537 A379475

Adjacent sequences: A378445 A378446 A378447 * A378449 A378450 A378451

Keyword

nonn

Author

Antti Karttunen, Nov 28 2024

Status

approved