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A035344 Expansion of 1/((1-x)*(1-4*x+2*x^2)). +0
2
1, 5, 19, 67, 231, 791, 2703, 9231, 31519, 107615, 367423, 1254463, 4283007, 14623103, 49926399, 170459391, 581984767, 1987020287, 6784111615, 23162405887, 79081400319, 270000789503, 921840357375 (list; graph; listen)
OFFSET

0,2

FORMULA

a(n)=2*A007052(n)-1. The sequence 0, 0, 1, 5, 19, ... is the binomial transform of the Pell numbers A000129, preceded by an additional 0. a(n)=(1+1/sqrt(2))(2+sqrt(2))^n+(1-1/sqrt(2))(2-sqrt(2))^n-1. - Paul Barry (pbarry(AT)wit.ie), Jul 16 2003

a(-1)=0, a(0)=1, a(n)=4*a(n-1)-2*a(n-2)+1 - Miklos Kristof (kristmikl(AT)freemail.hu), Mar 09 2005

MAPLE

a[ -1]:=0:a[0]:=1:for n from 1 to 50 do a[n]:=4*a[n-1]-2*a[n-2]+1 od: seq(a[n], n=0..50); (Kristof)

CROSSREFS

Partial sums of A007070.

Sequence in context: A005021 A067325 A121525 this_sequence A114277 A104496 A001435

Adjacent sequences: A035341 A035342 A035343 this_sequence A035345 A035346 A035347

KEYWORD

nonn

AUTHOR

njas

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Last modified July 26 23:19 EDT 2008. Contains 142293 sequences.


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