OFFSET
1,1
FORMULA
a(n)=Min{x^2 : x^2=nk+1}
EXAMPLE
Each square q appears in several progressions, i.e. in A000005(q-1) cases. Not necessarily as a first square. E.g. q=81 is minimal in {10k+1},{20k+1},{40k+1},{80k+1}, while not minimal in {3k+1} and 5 other progressions. In {16k+1} 49 comes before 81.
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Jun 08 2001
STATUS
approved