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A106469 Expansion of (1 + x^2)*(1 + 2*x)/(1 - x^2). 1
1, 2, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
LINKS
FORMULA
a(0)=1, a(n)=(2-0^((n-1)/2))(1-(-1)^n)+(2-0^(n/2))(1+(-1)^n)/2, n>1.
MATHEMATICA
CoefficientList[Series[(1+x^2)(1+2x)/(1-x^2), {x, 0, 95}], x] (* James C. McMahon, Feb 02 2024 *)
CROSSREFS
Row sums of A106468.
Sequence in context: A100374 A045841 A040003 * A082508 A327730 A365348
KEYWORD
easy,nonn
AUTHOR
Paul Barry, May 03 2005
STATUS
approved

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Last modified March 28 08:22 EDT 2024. Contains 371236 sequences. (Running on oeis4.)