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 A254864 Triangular table T(n,k) = n! / (n-floor(n/3^k))!, read by rows T(1,1), T(2,1), T(2,2), T(3,1), T(3,2), T(3,3), ... 4
 1, 1, 1, 3, 1, 1, 4, 1, 1, 1, 5, 1, 1, 1, 1, 30, 1, 1, 1, 1, 1, 42, 1, 1, 1, 1, 1, 1, 56, 1, 1, 1, 1, 1, 1, 1, 504, 9, 1, 1, 1, 1, 1, 1, 1, 720, 10, 1, 1, 1, 1, 1, 1, 1, 1, 990, 11, 1, 1, 1, 1, 1, 1, 1, 1, 1, 11880, 12, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 17160, 13, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 24024, 14, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS An auxiliary array for computing A088487. LINKS FORMULA T(n,k) = n! / (n-floor(n/3^k))! = A000142(n) / A000142(n-floor(n/A000244(k))). T(n,k) = Product_{m=1+(n-floor(n/(3^k))) .. n} m. EXAMPLE The first 27 rows of a triangular table: 1 1, 1 3, 1, 1 4, 1, 1, 1 5, 1, 1, 1, 1 30, 1, 1, 1, 1, 1 42, 1, 1, 1, 1, 1, 1 56, 1, 1, 1, 1, 1, 1, 1 504, 9, 1, 1, 1, 1, 1, 1, 1 720, 10, 1, 1, 1, 1, 1, 1, 1, 1 990, 11, 1, 1, 1, 1, 1, 1, 1, 1, 1 11880, 12, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 17160, 13, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 24024, 14, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 360360, 15, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 524160, 16, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 742560, 17, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 13366080, 306, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 19535040, 342, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 27907200, 380, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 586051200, 420, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 859541760, 462, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 1235591280, 506, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, ... 29654190720, 552, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, ... 43609104000, 600, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, ... 62990928000, 650, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, ... 1700755056000, 17550, 27, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, ... ... (the last ones truncated a bit). PROG (PARI) A254864bi(n, k) = prod(i=(1+(n-(n\(3^k)))), n, i); (Scheme) (define (A254864 n) (A254864bi (A002024 n) (A002260 n))) ;; The above function can then use either one of these: (define (A254864bi n k) (/ (A000142 n) (A000142 (- n (floor->exact (/ n (expt 3 k))))))) (define (A254864bi n k) (mul A000027 (+ 1 (- n (floor->exact (/ n (expt 3 k))))) n)) (define (mul intfun lowlim uplim) (let multloop ((i lowlim) (res 1)) (cond ((> i uplim) res) (else (multloop (+ 1 i) (* res (intfun i))))))) CROSSREFS The leftmost column: A254865. Cf. A000142, A000244, A088487, A254876. Sequence in context: A177058 A176921 A000503 * A111956 A024564 A084795 Adjacent sequences:  A254861 A254862 A254863 * A254865 A254866 A254867 KEYWORD nonn,tabl AUTHOR Antti Karttunen, Feb 09 2015 STATUS approved

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Last modified May 31 10:42 EDT 2020. Contains 334748 sequences. (Running on oeis4.)