The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A277325 Product of nonzero coefficients of the n-th Stern polynomial. 7
 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 2, 3, 1, 4, 1, 1, 1, 2, 2, 9, 2, 12, 3, 6, 1, 6, 4, 9, 1, 8, 1, 1, 1, 2, 2, 18, 2, 20, 9, 24, 2, 32, 12, 30, 3, 40, 6, 12, 1, 12, 6, 45, 4, 60, 9, 24, 1, 18, 8, 27, 1, 16, 1, 1, 1, 2, 2, 36, 2, 60, 18, 48, 2, 72, 20, 160, 9, 140, 24, 72, 2, 96, 32, 200, 12, 240, 30, 140, 3, 120, 40, 160, 6, 160, 12, 24, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,6 COMMENTS a(n) = product of nonzero terms on the n-th row of A125184. LINKS Antti Karttunen, Table of n, a(n) for n = 0..8192 FORMULA a(n) = A005361(A260443(n)). a(n) = A227349(A277020(n)). a(2n) = a(n). a(n) >= A277326(n). PROG (Scheme) (define (A277325 n) (A005361 (A260443 n))) ;; A standalone implementation: (define (A277325 n) (reduce * 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. A005361, A125184, A227349, A260443, A277020. Cf. also A277326 (lcm of nonzero coefficients) and A002487 (their sum). Sequence in context: A050431 A051574 A029386 * A240837 A369376 A060502 Adjacent sequences: A277322 A277323 A277324 * A277326 A277327 A277328 KEYWORD nonn AUTHOR Antti Karttunen, Oct 13 2016 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified September 19 04:19 EDT 2024. Contains 376004 sequences. (Running on oeis4.)