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A298734 a(n) = n-th term in periodic sequence repeating the divisors of n in decreasing order. 2
1, 1, 3, 4, 5, 3, 7, 1, 1, 5, 11, 1, 13, 7, 3, 16, 17, 1, 19, 10, 21, 11, 23, 1, 25, 13, 3, 4, 29, 3, 31, 16, 33, 17, 5, 1, 37, 19, 3, 1, 41, 21, 43, 22, 9, 23, 47, 3, 49, 25, 3, 4, 53, 3, 5, 1, 57, 29, 59, 1, 61, 31, 9, 64, 65, 33, 67, 34, 69, 5, 71, 1, 73, 37, 15, 4, 77, 3, 79, 1, 81, 41, 83, 1, 85, 43, 3, 1, 89, 10, 7, 46, 93, 47 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..20000

EXAMPLE

The divisors of 6 are 1, 2, 3, 6, which reversed is 6,3,2,1; repeating that produces the sequence 6, 3, 2, 1, 6, 3, 2, 1, 6, 3, 2, 1, ...; the 6th term in that sequence is 3, so a(6) = 3.

MAPLE

with(numtheory):

a:= n-> n/(l-> l[1+irem(n-1, nops(l))])(sort([divisors(n)[]])):

seq(a(n), n=1..100);  # Alois P. Heinz, Jan 29 2018

PROG

(PARI) a(n) = my(d=Vecrev(divisors(n))); if (n % #d, d[n % #d], 1); \\ Michel Marcus, Jan 26 2018

CROSSREFS

Cf. A122377 (n/a(n)), A033950 (indices of 1's).

Sequence in context: A033706 A121890 A178231 * A137926 A218342 A090395

Adjacent sequences:  A298731 A298732 A298733 * A298735 A298736 A298737

KEYWORD

nonn

AUTHOR

Franklin T. Adams-Watters, Jan 25 2018

STATUS

approved

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Last modified September 22 05:47 EDT 2019. Contains 327287 sequences. (Running on oeis4.)