OFFSET
1,1
FORMULA
a(n) ~ 4n^2 + O(n^2/log n). - Charles R Greathouse IV, Oct 24 2022
MATHEMATICA
Select[Table[4n^2 + 1, {n, 70}], ! PrimeQ[ # ] &]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Tanya Khovanova, Sep 03 2006
STATUS
approved