A277326 LCM of nonzero coefficients of the n-th Stern polynomial.

1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 2, 3, 1, 2, 1, 1, 1, 2, 2, 3, 2, 12, 3, 6, 1, 6, 2, 3, 1, 2, 1, 1, 1, 2, 2, 6, 2, 20, 3, 12, 2, 4, 12, 30, 3, 20, 6, 6, 1, 6, 6, 15, 2, 60, 3, 12, 1, 6, 2, 3, 1, 2, 1, 1, 1, 2, 2, 6, 2, 60, 6, 12, 2, 12, 20, 40, 3, 140, 12, 12, 2, 12, 4, 40, 12, 60, 30, 140, 3, 60, 20, 40, 6, 20, 6, 6, 1

Offset: 0

Author

Antti Karttunen, Oct 13 2016

Keywords

• nonn

Comments

a(n) = the least common multiple of nonzero terms on the n-th row of A125184.

Links

• Antti Karttunen, Table of n, a(n) for n = 0..8192
• Index entries for sequences related to lcm's

Crossrefs

Cf. A072411, A125184, A260443.

Differs from A277325 for the first time at n=13, where a(13) = 2, while A277325(13) = 4.

After n=0, differs from A277315 for the first time at n=21, where a(21) = 12, while A277315(21) = 4.

Programs

Scheme

(define (A277326 n) (A072411 (A260443 n)))
;; A standalone implementation:
(define (A277326 n) (reduce lcm 1 (filter positive? (A260443as_coeff_list n))))
(definec (A260443as_coeff_list n) (cond ((zero? n) (list)) ((= 1 n) (list 1)) ((even? n) (cons 0 (A260443as_coeff_list (/ n 2)))) (else (add_two_lists (A260443as_coeff_list (/ (- n 1) 2)) (A260443as_coeff_list (/ (+ n 1) 2))))))
(define (add_two_lists nums1 nums2) (let ((len1 (length nums1)) (len2 (length nums2))) (cond ((< len1 len2) (add_two_lists nums2 nums1)) (else (map + nums1 (append nums2 (make-list (- len1 len2) 0)))))))

Formula

a(n) = A072411(A260443(n)).

a(2n) = a(n).

a(n) <= A277325(n).