A039702 a(n) = n-th prime modulo 4.

2, 3, 1, 3, 3, 1, 1, 3, 3, 1, 3, 1, 1, 3, 3, 1, 3, 1, 3, 3, 1, 3, 3, 1, 1, 1, 3, 3, 1, 1, 3, 3, 1, 3, 1, 3, 1, 3, 3, 1, 3, 1, 3, 1, 1, 3, 3, 3, 3, 1, 1, 3, 1, 3, 1, 3, 1, 3, 1, 1, 3, 1, 3, 3, 1, 1, 3, 1, 3, 1, 1, 3, 3, 1, 3, 3, 1, 1, 1, 1, 3, 1, 3, 1, 3, 3, 1, 1, 1, 3, 3, 3, 3, 3, 3, 3, 1, 1, 3, 1, 3, 1, 3, 1, 3

Offset

1,1

Comments

Except for the first term, A100672(n) = (A039702(n)-1)/2 = parity of A005097. - Jeremy Gardiner, May 17 2008

Links

Nathaniel Johnston, Table of n, a(n) for n = 1..10000

Maple

seq(ithprime(n) mod 4, n=1..105); # Nathaniel Johnston, Jun 29 2011

Mathematica

Table[Mod[Prime[n], 4], {n, 105}] (* Nathaniel Johnston, Jun 29 2011 *)
Mod[Prime[Range[100]], 4] (* Vincenzo Librandi, May 06 2014 *)

Prog

(Haskell)
a039702 = (`mod` 4) . a000040  -- Reinhard Zumkeller, Feb 20 2012
(PARI) a(n)=prime(n)%4 \\ Charles R Greathouse IV, Jun 13 2013
(Magma) [p mod 4: p in PrimesUpTo(500)]; // Vincenzo Librandi, May 06 2014

Crossrefs

Cf. A000040, A039701, A039703-A039706, A100672, A005097, A038194, A007652, A039709-A039715.

Sequence in context: A257070 A289171 A231633 * A230294 A104483 A080717

Adjacent sequences: A039699 A039700 A039701 * A039703 A039704 A039705

Keyword

nonn,easy

Author

Clark Kimberling

Status

approved