The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A131378 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A131378

Starting with 0, the sequence a(n) changes from 0 to 1 or back when the next number n is a prime.
(history; published version)

#14 by Bruno Berselli at Tue Jul 23 08:52:03 EDT 2019

STATUS

reviewed

approved

#13 by Joerg Arndt at Tue Jul 23 07:25:43 EDT 2019

STATUS

proposed

reviewed

#12 by Jon E. Schoenfield at Fri Jul 19 22:52:39 EDT 2019

STATUS

editing

proposed

#11 by Jon E. Schoenfield at Fri Jul 19 22:52:37 EDT 2019

COMMENTS

Zero together with A071986 . - _Omar E. Pol, _, Feb 19 2011.

EXAMPLE

n = 0, 1, 2, 3, 4, 5, etc..

CROSSREFS

Cf. A071986 . - _Omar E. Pol, _, Feb 19 2011.

STATUS

proposed

editing

#10 by Omar E. Pol at Fri Jul 19 20:11:53 EDT 2019

STATUS

editing

proposed

#9 by Omar E. Pol at Fri Jul 19 20:11:37 EDT 2019

COMMENTS

Parity of A230980. - Omar E. Pol, Jul 19 2019

STATUS

approved

editing

#8 by Harvey P. Dale at Fri Jul 19 15:11:37 EDT 2019

STATUS

editing

approved

#7 by Harvey P. Dale at Fri Jul 19 15:11:35 EDT 2019

MATHEMATICA

nxt[{n_, a_}]:={n+1, Which[a==0&&PrimeQ[n+1], 1, a==1&&PrimeQ[n+1], 0, True, a]}; NestList[nxt, {0, 0}, 100][[All, 2]] (* Harvey P. Dale, Jul 19 2019 *)

STATUS

approved

editing

#6 by Charles R Greathouse IV at Fri Aug 24 10:49:59 EDT 2012

AUTHOR

_Paolo P. Lava & _ and _Giorgio Balzarotti (paoloplava(AT)gmail.com), _, Jul 04 2007

Discussion

Fri Aug 24

10:49

OEIS Server: https://oeis.org/edit/global/1825

#5 by T. D. Noe at Wed Sep 28 20:49:10 EDT 2011

AUTHOR

Paolo P. Lava & Giorgio Balzarotti (pplpaoloplava(AT)splgmail.atcom), Jul 04 2007

Discussion

Wed Sep 28

20:49

OEIS Server: https://oeis.org/edit/global/96