A266112 Characteristic function for A266114 (numbers that are least siblings in A263267-tree).

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

Offset

1

Comments

a(n) = 1 if there doesn't exist any k < n such that k - tau(k) = n - tau(n), and 0 otherwise. Here tau(n) = A000005(n), the number of divisors of n.

Also the characteristic function for the range of A082284 (with zero excluded).

Links

Antti Karttunen, Table of n, a(n) for n = 1..131072

Prog

(Scheme)
(define (A266112 n) (let ((parent (- n (A000005 n)))) (let loop ((k (- n 1))) (cond ((<= k parent) 1) ((= (- k (A000005 k)) parent) 0) (else (loop (- k 1)))))))

Crossrefs

Cf. A000005, A082284, A263267, A266114, A266115.

Cf. A266113 (partial sums).

Sequence in context: A267179 A244527 A243566 * A331990 A301849 A074332

Adjacent sequences: A266109 A266110 A266111 * A266113 A266114 A266115

Keyword

nonn

Author

Antti Karttunen, Dec 21 2015

Status

approved