A280694 Largest Lucas number (A000032) dividing n.

1, 2, 3, 4, 1, 3, 7, 4, 3, 2, 11, 4, 1, 7, 3, 4, 1, 18, 1, 4, 7, 11, 1, 4, 1, 2, 3, 7, 29, 3, 1, 4, 11, 2, 7, 18, 1, 2, 3, 4, 1, 7, 1, 11, 3, 2, 47, 4, 7, 2, 3, 4, 1, 18, 11, 7, 3, 29, 1, 4, 1, 2, 7, 4, 1, 11, 1, 4, 3, 7, 1, 18, 1, 2, 3, 76, 11, 3, 1, 4, 3, 2, 1, 7, 1, 2, 29, 11, 1, 18, 7, 4, 3, 47, 1, 4, 1, 7, 11, 4, 1, 3, 1, 4, 7, 2, 1, 18, 1, 11, 3, 7, 1

Offset

1,2

Links

Antti Karttunen, Table of n, a(n) for n = 1..15127

Formula

a(n) = n / A280695(n).

Other identities. For all n >= 1:

a(A000032(n)) = A000032(n).

a(A057854(n)) = A280696(A057854(n)).

a(A000045(n)) = A280699(n).

Prog

(Scheme)
;; A stand-alone program:
(define (A280694 n) (let loop ((l1 1) (l2 3) (lpd 1)) (cond ((> l1 n) (if (and (= 1 lpd) (even? n)) 2 lpd)) ((zero? (modulo n l1)) (loop l2 (+ l1 l2) l1)) (else (loop l2 (+ l1 l2) lpd)))))

Crossrefs

Cf. A000032, A054494, A280695, A280699.

Cf. A057854 (gives the positions n > 1 where this sequence and A280696 obtain equal values).

Sequence in context: A194742 A159798 A294236 * A270313 A343251 A327464

Adjacent sequences: A280691 A280692 A280693 * A280695 A280696 A280697

Keyword

nonn

Author

Antti Karttunen, Jan 11 2017

Status

approved