

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
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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 xgamma function at z=1.  Olivier Gérard, Jun 24 2012
For n>1, a(n) = Sum_{i=1..n1} floor(n/i)floor((n2)/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)*2sqrtint(n)^2
a(n)=if(n>4, A006218(n)A006218(n2)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



