Logo

Greetings from The On-Line Encyclopedia of Integer Sequences!

Hints

Search: id:A045896
Displaying 1-1 of 1 results found. page 1
     Format: long | short | internal | text      Sort: relevance | references | number      Highlight: on | off
A045896 Denominator of n/((n+1)(n+2)) = A026741/A045896. +0
8
1, 6, 6, 20, 15, 42, 28, 72, 45, 110, 66, 156, 91, 210, 120, 272, 153, 342, 190, 420, 231, 506, 276, 600, 325, 702, 378, 812, 435, 930, 496, 1056, 561, 1190, 630, 1332, 703, 1482, 780, 1640, 861, 1806, 946, 1980, 1035, 2162, 1128, 2352, 1225, 2550, 1326 (list; graph; listen)
OFFSET

0,2

COMMENT

Also period length divided by 2 of pairs (a,b), where a has period 2n-2 and b has period n.

LINKS

M. Kaneko, The Akiyama-Tanigawa algorithm for Bernoulli numbers, J. Integer Sequences, 3 (2000), #00.2.9.

Source

FORMULA

G.f.: (2x^3+3x^2+6x+1)/(1-x^2)^3.

a(n) = (n+1)*(n+2) if n odd; or (n+1)*(n+2)/2 if n even = (n+1)*(n+2)*(3-(-1)^n)/4 - C. Ronaldo (aga_new_ac(AT)hotmail.com), Dec 16 2004

MAPLE

seq((n+1)*(n+2)*(3-(-1)^n)/4, n=0..20); (C. Ronaldo)

with(combinat):seq(lcm(n+1, binomial(n+2, n)), n=0..50); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 20 2008

MATHEMATICA

Table[ LCM[ 2*n-2, n ]/2, {n, 40} ]

CROSSREFS

Cf. A045895, A026741.

Contribution from Johannes W. Meijer (meijgia(AT)hotmail.com), May 24 2009: (Start)

Factor of A160466.

(End)

Sequence in context: A161787 A092297 A073096 this_sequence A115046 A004983 A034695

Adjacent sequences: A045893 A045894 A045895 this_sequence A045897 A045898 A045899

KEYWORD

nonn,easy,frac,nice

AUTHOR

Ralf W. Grosse-Kunstleve (rwgk(AT)cci.lbl.gov)

page 1

Search completed in 0.002 seconds

Lookup | Welcome | Find friends | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
More pages | Superseeker | Maintained by N. J. A. Sloane (njas@research.att.com)

Last modified November 25 20:09 EST 2009. Contains 167514 sequences.


AT&T Labs Research