OFFSET
1,6
COMMENTS
Number of 1's in row n of A072528.
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
EXAMPLE
9 divided by 1,2...9 gives the remainders 0,1,0,1,4,3,2,1,0 of which 2,3,4 occur only once, so a(9)=3.
MATHEMATICA
Table[Count[Tally[Mod[n, Range[n]]], _?(#[[2]]==1&)], {n, 90}] (* Harvey P. Dale, Aug 17 2023 *)
PROG
(PARI) a(n)=v=vector(n+1); for(d=1, n, t=(n%d)+1; v[t]=v[t]+1); sum(i=1, n, v[i]==1)
CROSSREFS
KEYWORD
nonn
AUTHOR
Ralf Stephan, Oct 13 2013
STATUS
approved