OFFSET
1,2
COMMENTS
Also known as the Beprisque numbers.
LINKS
T. D. Noe, Table of n, a(n) for n = 1..1000
Planet Math, Beprisque numbers
EXAMPLE
a(1) = 2 since 2 lies between 1(square) and 3(prime).
a(2) = 3 since 3 lies between 2(prime) and 4(square).
MATHEMATICA
nn = 100; Sort[Select[Range[0, nn], PrimeQ[#^2 + 2] &]^2 + 1, Select[Range[nn], PrimeQ[#^2 - 2] &]^2 - 1] (* T. D. Noe, Aug 29 2012 *)
Select[Range[15000], AnyTrue[#+{1, -1}, PrimeQ]&&AnyTrue[{Sqrt[#-1], Sqrt[ #+1]}, IntegerQ]&] (* Harvey P. Dale, Feb 06 2023 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Gaurav Kumar, Jul 29 2009
EXTENSIONS
Definition clarified by R. J. Mathar, Aug 08 2009
Number 1 added by WG Zeist, Aug 28 2012
STATUS
approved