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A277326 LCM of nonzero coefficients of the n-th Stern polynomial. 6
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,6

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

FORMULA

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

a(2n) = a(n).

a(n) <= A277325(n).

PROG

(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)))))))

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.

Sequence in context: A262561 A264990 A277315 * A050431 A051574 A029386

Adjacent sequences:  A277323 A277324 A277325 * A277327 A277328 A277329

KEYWORD

nonn

AUTHOR

Antti Karttunen, Oct 13 2016

STATUS

approved

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Last modified July 19 12:35 EDT 2019. Contains 325159 sequences. (Running on oeis4.)