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A092338 Number of numbers d with n mod d <= 1. 1
1, 2, 3, 4, 4, 5, 5, 5, 6, 6, 5, 7, 7, 5, 7, 8, 6, 7, 7, 7, 9, 7, 5, 9, 10, 6, 7, 9, 7, 9, 9, 7, 9, 7, 7, 12, 10, 5, 7, 11, 9, 9, 9, 7, 11, 9, 5, 11, 12, 8, 9, 9, 7, 9, 11, 11, 11, 7, 5, 13, 13, 5, 9, 12, 10, 11, 9, 7, 9, 11, 9, 13, 13, 5, 9, 11, 9, 11, 9, 11, 14, 8, 5, 13, 15, 7, 7, 11, 9, 13 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

FORMULA

G.f.: x^2/(x - 1) + ((1 + x)*(log(1 - x) + psi(1, x)))/log(x)  where psi(1,x) is the logarithmic derivative of the x-gamma function at z=1. - Olivier Gérard, Jun 24 2012

For n>1, a(n) = Sum_{i=1..n-1} floor(n/i)-floor((n-2)/i). - Wesley Ivan Hurt, Sep 13 2017

PROG

(Haskell)

a092338 n = length $ filter (<= 1) $ map (mod n) [1..n]

-- Reinhard Zumkeller, Jul 04 2012

(PARI) A006218(n)=sum(k=1, sqrtint(n), n\k)*2-sqrtint(n)^2

a(n)=if(n>4, A006218(n)-A006218(n-2)-1, n) \\ Charles R Greathouse IV, Sep 13 2017

CROSSREFS

Sequence in context: A070546 A034586 A268383 * A199769 A030601 A049839

Adjacent sequences:  A092335 A092336 A092337 * A092339 A092340 A092341

KEYWORD

nonn,easy

AUTHOR

Reinhard Zumkeller, Mar 18 2004

EXTENSIONS

Wrong comment removed by Reinhard Zumkeller, Jul 04 2012

STATUS

approved

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Last modified October 22 20:36 EDT 2017. Contains 293777 sequences.