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A267478 Primes which are squares (mod 55). 1
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

5, 11 and all primes congruent to 1, 4, 9, 14, 16, 26, 31, 34, 36, or 49 (mod 55). - Robert Israel, Jan 15 2016

LINKS

Table of n, a(n) for n=1..57.

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

PROG

(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

CROSSREFS

Cf. A106904 and adjacent sequences.

Cf. A191036.

Sequence in context: A052228 A105910 A023259 * A280081 A057470 A038580

Adjacent sequences:  A267475 A267476 A267477 * A267479 A267480 A267481

KEYWORD

nonn

AUTHOR

M. F. Hasler, Jan 15 2016

STATUS

approved

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Last modified September 22 11:12 EDT 2021. Contains 347606 sequences. (Running on oeis4.)