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 A055515 (2^n -1)/product(2^p -1) where the product is over all distinct primes p that divide n. 0
 1, 1, 1, 5, 1, 3, 1, 85, 73, 11, 1, 195, 1, 43, 151, 21845, 1, 12483, 1, 11275, 2359, 683, 1, 798915, 1082401, 2731, 19173961, 704555, 1, 1649373, 1, 1431655765, 599479, 43691, 8727391, 3272356035, 1, 174763, 9588151, 11822705675, 1, 1649061309, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 LINKS FORMULA For p prime, a(p) = 1. - Michel Marcus, May 18 2014 For p prime, a(p^2) = A051156(n). - Michel Marcus, May 18 2014 EXAMPLE a(12) = (2^12 -1)/((2^2 -1) (2^3 -1)) = 195. PROG (PARI) a(n) = my(f = factor(n)); (2^n-1)/prod(i=1, #f~, 2^f[i, 1] -1); \\ Michel Marcus, May 18 2014 CROSSREFS Sequence in context: A329374 A115638 A342375 * A338096 A215010 A136744 Adjacent sequences:  A055512 A055513 A055514 * A055516 A055517 A055518 KEYWORD easy,nonn AUTHOR Leroy Quet, Jul 03 2000 STATUS approved

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Last modified May 13 22:47 EDT 2021. Contains 343868 sequences. (Running on oeis4.)