A045447 - OEIS

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A045447

Primes congruent to {0, 5} mod 7.

5, 7, 19, 47, 61, 89, 103, 131, 173, 229, 257, 271, 313, 383, 397, 439, 467, 509, 523, 593, 607, 677, 691, 719, 733, 761, 859, 887, 929, 971, 1013, 1069, 1097, 1153, 1181, 1223, 1237, 1279, 1307, 1321, 1433

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OFFSET

1,1

COMMENTS

Because 7 is the only prime congruent to 0 mod 7, it is more efficient to search only for primes that are congruent to 5 mod 7 and then insert 7 as the second term of the sequence (see the second Mathematica program below). - Harvey P. Dale, Jun 24 2017

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

MATHEMATICA

Select[Prime[Range[200]], MemberQ[{0, 5}, Mod[#, 7]]&] (* Vincenzo Librandi, Aug 13 2012 *)

Insert[Select[Prime[Range[500]], Mod[#, 7]==5&], 7, 2] (* Harvey P. Dale, Jun 24 2017 *)

PROG

(Magma) [ p: p in PrimesUpTo(2000) | p mod 7 in {0, 5} ]; // Vincenzo Librandi, Aug 13 2012

CROSSREFS

Cf. A000040.

Sequence in context: A288608 A079361 A162268 * A337439 A159048 A290415

Adjacent sequences: A045444 A045445 A045446 * A045448 A045449 A045450

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

STATUS

approved