A092446 Numbers n such that if P = 10*n^2+1, then P, P+6, P+12 and P+18 are all primes.

1, 2, 5, 8, 20, 83, 110, 128, 141, 216, 223, 334, 506, 810, 825, 867, 1086, 1171, 1861, 2178, 2295, 2680, 2911, 3803, 4884, 7737, 8010, 8457, 8520, 9858, 9882, 10379, 11871

Offset

1,2

Links

Table of n, a(n) for n=1..33.

Example

a(3) = 5; 10*5^2+1 = 251. 251+6 = 257; 251+12 = 263; 251+18=269. 251, 257, 263 and 269 are all primes.

Mathematica

pQ[n_]:=Module[{x=10n^2+1}, And@@PrimeQ/@(x+ {0, 6, 12, 18})]; Select[Range[12000], pQ]  (* Harvey P. Dale, Mar 22 2011 *)

Crossrefs

Sequence in context: A139407 A107384 A205596 * A087077 A200276 A168081

Adjacent sequences: A092443 A092444 A092445 * A092447 A092448 A092449

Keyword

nonn

Author

Ray G. Opao, Mar 24 2004

Extensions

More terms from Harvey P. Dale, Mar 22 2011.

Status

approved