OFFSET
1,1
COMMENTS
Sequence lists squares of prime numbers that end in 1 or 9.
EXAMPLE
Prime 11*11=121 and 19*19=361; 121 and 361 are terms of this sequence.
Prime 13*13=169 and 17*17=289; 169 and 289 are not terms of this sequence.
MATHEMATICA
Select[Range[360], PrimeQ[#] && Mod[#^2, 30] == 1 &]^2 (* Amiram Eldar, Dec 28 2019 *)
PROG
(PARI) isok(m) = issquare(m) && isprime(sqrtint(m)) && ((m % 30) == 1); \\ Michel Marcus, Dec 26 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Harry E. Neel, Dec 24 2019
EXTENSIONS
Deleted an incorrect crossreference. - Harry E. Neel, Jan 22 2020
STATUS
approved