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 A057449 Product of differences between consecutive positive divisors of n. 2
 1, 1, 2, 2, 4, 3, 6, 8, 12, 15, 10, 12, 12, 35, 40, 64, 16, 81, 18, 100, 112, 99, 22, 192, 80, 143, 216, 588, 28, 600, 30, 1024, 352, 255, 224, 1944, 36, 323, 520, 2400, 40, 3087, 42, 3388, 2880, 483, 46, 12288, 252, 5625, 952, 6084, 52, 19683, 1056, 14112, 1216 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Row products of triangle A193829, if n >= 2. - Omar E. Pol, Aug 31 2011 When p is prime a(p) = p-1. - Michel Marcus, May 15 2014 LINKS Alois P. Heinz, Table of n, a(n) for n = 1..10000 FORMULA a(n) = product(A027750(n,k+1)-A027750(n,k): k=1..A001221(n)-1. - Reinhard Zumkeller, Jun 23 2013 EXAMPLE Since positive divisors of 12 are 1, 2, 3, 4, 6 and 12, a(12) = (2-1) *(3-2) *(4-3) *(6-4) *(12-6) = 1 *1 *1 *2 *6 = 12. MATHEMATICA Times@@Differences[Divisors[#]]&/@Range[80]  (* Harvey P. Dale, Apr 20 2011 *) PROG (Haskell) a057449 = product . a193829_row  -- Reinhard Zumkeller, Jun 23 2013 (PARI) a(n) = {my(d = divisors(n)); prod(i=1, #d-1, d[i+1] - d[i]); } \\ Michel Marcus, May 15 2014 CROSSREFS Sequence in context: A293170 A101200 A122585 * A286931 A265701 A007439 Adjacent sequences:  A057446 A057447 A057448 * A057450 A057451 A057452 KEYWORD nonn,look AUTHOR Leroy Quet, Sep 25 2000 STATUS approved

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Last modified December 11 04:29 EST 2018. Contains 318049 sequences. (Running on oeis4.)