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Search: id:A109613
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(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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a(n) = A052928(n) + 1 = 2*A004526(n) + 1.
a(n) = A028242(n) + A110654(n).
Diagonal sums of number triangle A113126. - Paul Barry (pbarry(AT)wit.ie), Oct 14 2005
When partitioning a convex n-gon by all the diagonals, the maximum number of sides in resulting polygons is 2*floor(n/2)+1 = a(n-1) (from Moscow Olympiad problem 1950) - Tanya Khovanova (tanyakh(AT)yahoo.com), Apr 06 2008
Its ordinal transform is A000034 [From Paolo P. Lava (ppl(AT)spl.at), Jun 25 2009]
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FORMULA
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a(n) = 2*floor(n/2) + 1.
a(n) = A052938(n-2) + A084964(n-2) for n>1. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Aug 27 2005
G.f.: (1+x+x^2+x^3)/(1-x^2)^2; - Paul Barry (pbarry(AT)wit.ie), Oct 14 2005
a(n)=n+[1+(-1)^n]/2, with n>=0 - Paolo P. Lava (ppl(AT)spl.at), May 08 2007
a(n)=2*a(n-2)-a(n-4); a(0)=1, a(1)=1, a(2)=3, a(3)=3. [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Nov 03 2008]
a(n)=A001477(n)+A059841(n). [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Mar 31 2009]
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CROSSREFS
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Cf. A063196, A110660.
Adjacent sequences: A109610 A109611 A109612 this_sequence A109614 A109615 A109616
Sequence in context: A117767 A063196 A127630 this_sequence A073737 A133908 A111213
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KEYWORD
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nonn
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AUTHOR
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Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Aug 01 2005
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