A027021 - OEIS

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A027021

a(n) = T(n,n) + T(n,m+1) + ... + T(n,n), where m=[ (n+2)/2 ], T given by A027011.

1, 1, 6, 7, 36, 56, 181, 317, 826, 1531, 3576, 6832, 15021, 29201, 61966, 121727, 252796, 499816, 1024101, 2033077, 4130226, 8220851, 16609456, 33115232, 66669661, 133067881, 267285606, 533860567, 1070731476, 2139602456

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,3

LINKS

Table of n, a(n) for n=1..30.

FORMULA

G.f.: x(-4x^6+10x^4-x^3-x+1)/[(1-x^2)(1-2x)(1+x-x^2)(1-x-x^2)].

CROSSREFS

Sequence in context: A037411 A025626 A175167 * A013627 A248850 A294728

Adjacent sequences: A027018 A027019 A027020 * A027022 A027023 A027024

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved