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A027931 T(n,2n-8), T given by A027926. 2
1, 2, 5, 13, 34, 88, 221, 530, 1204, 2587, 5270, 10220, 18955, 33775, 58060, 96647, 156299, 246280, 379051, 571103, 843944, 1225258, 1750255, 2463232, 3419366, 4686761, 6348772, 8506630, 11282393, 14822249, 19300198, 24922141 (list; graph; refs; listen; history; text; internal format)
OFFSET

4,2

LINKS

Table of n, a(n) for n=4..35.

Index entries for linear recurrences with constant coefficients, signature (9,-36,84,-126,126,-84,36,-9,1).

FORMULA

a(n)=sum(binomial(n-k, 8-2k), k=0..4). - Len Smiley, Oct 20 2001

G.f.: -x^4*(1-7*x+23*x^2-44*x^3+55*x^4-44*x^5+23*x^6-7*x^7+x^8) / (x-1)^9 . - R. J. Mathar, Oct 31 2015

MAPLE

A027931 := proc(n)

    add(binomial(n-k, 8-2*k), k=0..4) ;

end proc: # R. J. Mathar, Oct 31 2015

CROSSREFS

Cf. A228074.

Sequence in context: A122024 A252932 A318234 * A218481 A267905 A209230

Adjacent sequences:  A027928 A027929 A027930 * A027932 A027933 A027934

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified January 21 11:00 EST 2019. Contains 319351 sequences. (Running on oeis4.)