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A045453
Primes congruent to {0, 1} mod 5.
4
5, 11, 31, 41, 61, 71, 101, 131, 151, 181, 191, 211, 241, 251, 271, 281, 311, 331, 401, 421, 431, 461, 491, 521, 541, 571, 601, 631, 641, 661, 691, 701, 751, 761, 811, 821, 881, 911, 941, 971, 991, 1021, 1031, 1051, 1061, 1091, 1151, 1171, 1181, 1201, 1231
OFFSET
1,1
COMMENTS
Being a subset of A141158, this is also a subset of the primes of form x^2 - 5y^2. - Tito Piezas III, Dec 28 2008
LINKS
FORMULA
a(n) = A030430(n-1) for all n >= 2. - M. F. Hasler, Jan 15 2018
EXAMPLE
a(1) = 5 is the first primes that is congruent to 0 or 1, modulo 5.
a(2) = 11 is the first prime congruent to 1 modulo 5, and therefore (since there is no other prime congruent to 0 mod 5) the second term of this sequence.
a(10^k) = (181, 2791, 38201, 479771, 5803381, 67881871, 776580131, ...) for k = 1, 2, 3, ...
MATHEMATICA
Select[Prime@Range[210], MemberQ[{0, 1}, Mod[ #, 5]] &] (* Ray Chandler, Dec 06 2006 *)
PROG
(Magma) [ p: p in PrimesUpTo(1300) | p mod 5 in {0, 1} ]; // Vincenzo Librandi, Aug 13 2012
(PARI) A045453_vec(Nmax)=select( p->p%5<2, primes([1, Nmax])) \\ or:
A045453(n)=forprime(p=1, , p%5>1||n--||return(p)) \\ M. F. Hasler, Jan 15 2018
CROSSREFS
Same as A030430 with addition of the only prime congruent to 0 (mod 5), a(1) = 5.
Cf. A000040.
Sequence in context: A239842 A092963 A191069 * A052228 A371670 A105910
KEYWORD
nonn,easy
EXTENSIONS
Extended by Ray Chandler, Nov 28 2003
Checked by Neven Juric (neven.juric(AT)apis-it.hr), Feb 04 2008
Edited and a(1000) double checked by M. F. Hasler, Jan 15 2018
STATUS
approved