The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A123640

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A123640

a(n) = A065120(n) modulo 2.
(history; published version)

#11 by Peter Luschny at Wed Jan 24 07:57:18 EST 2024

STATUS

proposed

approved

#10 by Joerg Arndt at Wed Jan 24 02:40:24 EST 2024

STATUS

editing

proposed

#9 by Joerg Arndt at Wed Jan 24 02:39:55 EST 2024

NAME

Consider the 2^n compositions of n per row and mark only those ending in an odd part.

a(n) = A065120(n) modulo 2.

COMMENTS

Previous name was: Consider the 2^n compositions of n per row and mark only those ending in an odd part.

FORMULA

a(n) = Mod(A065120(n),2).

EXTENSIONS

New name using given formula, Joerg Arndt, Jan 24 2024

STATUS

approved

editing

#8 by Joerg Arndt at Sun Feb 09 04:13:17 EST 2014

STATUS

proposed

approved

#7 by Michel Marcus at Sun Feb 09 01:28:09 EST 2014

STATUS

editing

proposed

#6 by Michel Marcus at Sun Feb 09 01:27:29 EST 2014

PROG

(PARI) lista(nn) = {my(v = vector(nn)); v[1] = 1; for (i=2, nn, v[i] = mg(i-1)*v[(i+1)\2]; ); for (i=1, nn, print1(valuation(v[i], 2) % 2, ", "); ); } \\ Michel Marcus, Feb 09 2014

STATUS

approved

editing

#5 by Russ Cox at Sat Mar 31 13:23:38 EDT 2012

AUTHOR

_Alford Arnold (Alford1940(AT)aol.com), _, Oct 04 2006

Discussion

Sat Mar 31

13:23

OEIS Server: https://oeis.org/edit/global/889

#4 by Russ Cox at Sat Mar 31 13:22:27 EDT 2012

EXTENSIONS

More terms from _Nathaniel Johnston (nathaniel(AT)nathanieljohnston.com), _, Apr 30 2011

Discussion

Sat Mar 31

13:22

OEIS Server: https://oeis.org/edit/global/888

#3 by Nathaniel Johnston at Sat Apr 30 15:49:58 EDT 2011

STATUS

proposed

approved

#2 by Nathaniel Johnston at Sat Apr 30 15:49:54 EDT 2011

DATA

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

FORMULA

a(n) = Mod(A065120(n),2).

EXAMPLE

A065120 begins 0 , 1 , 2 , 1 , 3 , 2 , 1 , 1 , 4 , 3 , 2 , 2 , 1 , 1 , 1 , 1 , ...

therefore

Therefore this sequence begins 0 , 1 , 0 , 1 , 1 , 0 , 1 , 1 , 0 , 1 , 0 , 0 , 1 , 1 , 1 , 1 , ...

CROSSREFS

Cf. A001045 , A065120 , A123638 , A123639 , A123641.

KEYWORD

easy,more,nonn

EXTENSIONS

More terms from Nathaniel Johnston (nathaniel(AT)nathanieljohnston.com), Apr 30 2011

STATUS

approved

proposed