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

%I A277326 #8 Oct 26 2016 15:18:26
%S A277326 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,
%T A277326 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,
%U A277326 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
%N A277326 LCM of nonzero coefficients of the n-th Stern polynomial.
%C A277326 a(n) = the least common multiple of nonzero terms on the n-th row of A125184.
%H A277326 Antti Karttunen, <a href="/A277326/b277326.txt">Table of n, a(n) for n = 0..8192</a>
%H A277326 <a href="/index/Lc#lcm">Index entries for sequences related to lcm's</a>
%F A277326 a(n) = A072411(A260443(n)).
%F A277326 a(2n) = a(n).
%F A277326 a(n) <= A277325(n).
%o A277326 (Scheme)
%o A277326 (define (A277326 n) (A072411 (A260443 n)))
%o A277326 ;; A standalone implementation:
%o A277326 (define (A277326 n) (reduce lcm 1 (filter positive? (A260443as_coeff_list n))))
%o A277326 (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))))))
%o A277326 (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)))))))
%Y A277326 Cf. A072411, A125184, A260443.
%Y A277326 Differs from A277325 for the first time at n=13, where a(13) = 2, while A277325(13) = 4.
%Y A277326 After n=0, differs from A277315 for the first time at n=21, where a(21) = 12, while A277315(21) = 4.
%K A277326 nonn
%O A277326 0,6
%A A277326 _Antti Karttunen_, Oct 13 2016