A072608 - OEIS

A072608

Parity of remainder Mod(prime(n),n) = A004648(n).

0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0

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OFFSET

1,1

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = Mod(Mod(prime(n), n), 2) = Mod(A004648(n), 2).

EXAMPLE

n=25:p(25)=97,Mod[97,25]=22, a(25)=Mod[22,2]=0. With increasing n, a(n) alternates:...010101..,followed after by a range consisting only of 1-s. This secondary alternation also goes on.

MATHEMATICA

mm[x_] := Mod[Mod[Prime[x], x], 2] Table[mm[w], {w, 1, 256}]

Table[Mod[Mod[Prime[n], n], 2], {n, 110}] (* Harvey P. Dale, Apr 22 2016 *)

PROG

(Haskell)

a072608 n = a000040 n `mod` n `mod` 2 -- Reinhard Zumkeller, Dec 16 2013

(PARI) a(n)=prime(n)%n%2 \\ Charles R Greathouse IV, Feb 09 2017

CROSSREFS

Cf. A004648.

Sequence in context: A320007 A072165 A358224 * A295304 A171386 A189816

Adjacent sequences: A072605 A072606 A072607 * A072609 A072610 A072611

KEYWORD

nice,nonn,easy

AUTHOR

Labos Elemer, Jun 24 2002

STATUS

approved