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A027010 a(n) = Sum_{k=floor((n+1)/2)..n} T(k,n-k); i.e., a(n) is the n-th diagonal sum of left-justified array T given by A026998. 1
1, 1, 2, 5, 6, 13, 17, 29, 43, 64, 100, 144, 223, 326, 492, 733, 1089, 1634, 2421, 3626, 5389, 8041, 11985, 17847, 26624, 39640, 59112, 88059, 131242, 195592, 291433, 434369, 647218, 964581, 1437374, 2142013, 3192113, 4756821 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

FORMULA

G.f.: x*(2x^3-x^2+1)/((1-x)*(1-2x^2-x^3+x^4)).

MATHEMATICA

CoefficientList[Series[(2 x^3 - x^2 + 1) / ((1 - x) (1 - 2 x^2 - x^3 + x^4)), {x, 0, 40}], x] (* Vincenzo Librandi, Aug 03 2017 *)

CROSSREFS

Sequence in context: A283684 A323348 A181314 * A038191 A321472 A087128

Adjacent sequences:  A027007 A027008 A027009 * A027011 A027012 A027013

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified February 16 20:45 EST 2019. Contains 320189 sequences. (Running on oeis4.)