A267478 Primes which are squares (mod 55).
5, 11, 31, 59, 71, 89, 179, 181, 191, 199, 229, 251, 269, 311, 331, 379, 389, 401, 419, 421, 449, 499, 509, 521, 599, 619, 631, 641, 661, 691, 709, 719, 751, 829, 839, 859, 881, 911, 929, 971, 991, 1021, 1039, 1049, 1061, 1109, 1171, 1181, 1259, 1279, 1291, 1301, 1321, 1409, 1439, 1489, 1499
Offset: 1
Keywords
Programs
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Maple
S55:= {seq(x^2 mod 55, x=0..27)}: select(t -> member(t mod 55, S55), [seq(ithprime(i),i=1..1000)]); # Robert Israel, Jan 15 2016 -
Mathematica
Join[{5,11},Select[Prime[Range[250]],MemberQ[{1,4,9,14,16,26,31,34,36,49},Mod[#,55]]&]] (* Harvey P. Dale, Jan 17 2022 *) -
PARI
select(p->issquare(Mod(p,55))&&isprime(p),[1..1500]) \\ It would be more efficient to select only among primes, replacing [1..1500] by primes([1,1500]), in which case the isprime() condition can be omitted from the selection function. But we wanted to provide a universally valid characteristic function in the 1st argument of select(). - M. F. Hasler, Jan 15 2016
Comments