OFFSET
1,1
COMMENTS
Or numbers n such that the smallest prime divisor of n^2+1 is A002313(13).
a(n)== 10 or 192 (mod 202).
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
EXAMPLE
414 is in the sequence because 414^2+1= 101*1697.
MATHEMATICA
lst={}; Do[If[FactorInteger[n^2+1][[1, 1]]==101, AppendTo[lst, n]], {n, 2, 10000}]; lst
p = 101; ps = Select[Range[p - 1], Mod[#, 4] != 3 && PrimeQ[#] &]; Select[Range[13000], Divisible[(nn = #^2 + 1), p] && ! Or @@ Divisible[nn, ps] &] (* Amiram Eldar, Aug 16 2019 *)
Select[Range[13000], FactorInteger[#^2+1][[1, 1]]==101&] (* Harvey P. Dale, Oct 01 2024 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Michel Lagneau, Oct 08 2014
STATUS
approved