The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A212322 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A212322

Number of compositions of n such that no two adjacent parts are equal, and the first part is not equal to the last part if there is more than one part.
(history; published version)

#49 by Peter Luschny at Sat Mar 07 08:49:55 EST 2020

STATUS

reviewed

approved

#48 by Joerg Arndt at Sat Mar 07 08:43:56 EST 2020

STATUS

proposed

reviewed

#47 by F. Chapoton at Sat Mar 07 07:52:03 EST 2020

STATUS

editing

proposed

#46 by F. Chapoton at Sat Mar 07 07:52:00 EST 2020

PROG

... Q = []

... for comp in Compositions(n) :

...... if len(comp) == 1 or all([ comp[k] != comp[k+1] for k in range(-1, len(comp)-1) ]):

......... Q.append(comp)

... print (len(Q), ", ", )

STATUS

approved

editing

Discussion

Sat Mar 07

07:52

F. Chapoton: adapt sage code for python3

#45 by Alois P. Heinz at Sat Dec 30 09:43:53 EST 2017

STATUS

proposed

approved

#44 by Jean-François Alcover at Sat Dec 30 09:41:38 EST 2017

STATUS

editing

proposed

#43 by Jean-François Alcover at Sat Dec 30 09:41:06 EST 2017

MATHEMATICA

terms = 39;

gf = 1 + Sum[x^k/(1 + x^k)^2, {k, 1, terms}]/(1 - Sum[x^k/(1 + x^k), {k, 1, terms}]) + Sum[x^(2 k)/(1 + x^k), {k, 1, terms}] + O[x]^terms;

CoefficientList[gf, x] (* Jean-François Alcover, Dec 30 2017 *)

STATUS

approved

editing

#42 by Joerg Arndt at Sat Dec 09 03:59:36 EST 2017

STATUS

proposed

approved

#41 by Jon E. Schoenfield at Sat Dec 09 03:39:07 EST 2017

STATUS

editing

proposed

#40 by Jon E. Schoenfield at Sat Dec 09 03:39:03 EST 2017

NAME

Number of compositions of n so such that no two adjacent parts are equal, and the first part is not equal to the last part if there is more than one part.

STATUS

approved

editing