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A340867 a(n) = (prime(n) - a(n-1)) mod 4; a(0)=0. 1
0, 2, 1, 0, 3, 0, 1, 0, 3, 0, 1, 2, 3, 2, 1, 2, 3, 0, 1, 2, 1, 0, 3, 0, 1, 0, 1, 2, 1, 0, 1, 2, 1, 0, 3, 2, 1, 0, 3, 0, 1, 2, 3, 0, 1, 0, 3, 0, 3, 0, 1, 0, 3, 2, 1, 0, 3, 2, 1, 0, 1, 2, 3, 0, 3, 2, 3, 0, 1, 2, 3, 2, 1, 2, 3, 0, 3, 2, 3, 2, 3, 0, 1, 2, 3, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..85.

Simon Strandgaard, Visualization

FORMULA

a(n) = A008347(n) mod 4.

EXAMPLE

a(1) = ( 2 - 0) mod 4 = 2,

a(2) = ( 3 - 2) mod 4 = 1,

a(3) = ( 5 - 1) mod 4 = 0,

a(4) = ( 7 - 0) mod 4 = 3,

a(5) = (11 - 3) mod 4 = 0.

MATHEMATICA

a[0] = 0; a[n_] := a[n] = Mod[Prime[n] - a[n - 1], 4]; Array[a, 100, 0] (* Amiram Eldar, Jan 30 2021 *)

PROG

(Ruby) require 'prime'

values = [0]

Prime.first(50).each do |prime|

    values << (prime-values[-1]) % 4

end

p values

CROSSREFS

Cf. A008347, A339448.

Sequence in context: A159813 A157409 A245960 * A178616 A165252 A127373

Adjacent sequences:  A340864 A340865 A340866 * A340868 A340869 A340870

KEYWORD

nonn

AUTHOR

Simon Strandgaard, Jan 24 2021

STATUS

approved

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Last modified September 23 02:04 EDT 2021. Contains 347609 sequences. (Running on oeis4.)