OFFSET
1,2
COMMENTS
For examples of longer similar chains, if n = 1, 321, or 63879, the polynomial produces 7 consecutive prime terms (including n). - Harvey P. Dale, May 04 2024
MATHEMATICA
Do[s=5*n^2+5*n+1; s1=5*(n+1)^2+5*(n+1)+1; s2=5*(n+2)^2+5*(n+2)+1; s3=5*(n+3)^2+5*(n+3)+1; s4=5*(n+4)^2+5*(n+4)+1; If[PrimeQ[s]&&PrimeQ[s1]&&PrimeQ[s2]&& PrimeQ[s3]&&PrimeQ[s4], Print[n]], {n, 1, 100000}]
SequencePosition[Table[If[PrimeQ[5n^2+5n+1], 1, 0], {n, 100000}], {1, 1, 1, 1, 1}][[;; , 1]] (* Harvey P. Dale, May 04 2024 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Labos Elemer, Dec 12 2003
STATUS
approved