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A066451 a(n) is the number of integers k > 0 such that (n*k+1)/(k^2+1) is an integer. 1
1, 1, 2, 1, 2, 1, 3, 1, 2, 1, 2, 2, 3, 1, 2, 1, 3, 1, 2, 1, 3, 2, 3, 1, 2, 1, 3, 1, 2, 1, 3, 2, 3, 1, 2, 1, 3, 2, 2, 1, 2, 2, 4, 1, 2, 1, 3, 1, 2, 1, 2, 2, 3, 1, 3, 1, 5, 1, 2, 1, 2, 2, 3, 1, 2, 1, 3, 1, 2, 1, 2, 3, 4, 1, 2, 1, 3, 1, 2, 2, 2, 2, 4, 1, 2, 1, 3, 1, 3, 1, 3, 2, 3, 1, 2, 1, 3, 1, 2, 1, 2, 2, 3, 1, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..105.

EXAMPLE

a(57)=5 because (57*k+1)/(k^2+1) is an integer for k = 1,2,5,7,57.

CROSSREFS

Sequence in context: A195155 A178544 A161506 * A328048 A091090 A305052

Adjacent sequences:  A066448 A066449 A066450 * A066452 A066453 A066454

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Dec 29 2001

STATUS

approved

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Last modified November 12 09:01 EST 2019. Contains 329052 sequences. (Running on oeis4.)