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A089941 Row sums of triangle A089940. 1
1, 2, 4, 9, 19, 42, 90, 197, 424, 923, 1989, 4315, 9300, 20129, 43374, 93724, 201888, 435713, 938218, 2022972, 4354569, 9382489, 20190181, 43477688, 93534469, 201326672, 433017364, 931701321, 2003520121, 4309597827, 9265723250 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..30.

FORMULA

a(n)=sum{k=0..n, Bin(n+k, floor((n-k)/2))}.

Conjecture: +n*(n+6)*(n-5)*a(n) -(n+6)*(n^2-3*n-6)*a(n-1) -2*(n+6)*(3*n^2-20*n

+27)*a(n-2) +(n+6)*(3*n^2-19*n+36)*a(n-3) +2*(4*n-15)*(n-3)*(n+6)*a(n-4) +4*(n-3

)*(n-4)*(n+6)*a(n-5)=0. - R. J. Mathar, Dec 10 2014

CROSSREFS

Sequence in context: A275862 A036622 A001384 * A307464 A127681 A192923

Adjacent sequences:  A089938 A089939 A089940 * A089942 A089943 A089944

KEYWORD

easy,nonn

AUTHOR

Paul Barry, Nov 16 2003

STATUS

approved

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Last modified November 28 22:15 EST 2021. Contains 349415 sequences. (Running on oeis4.)