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A134389 A transform of Floor((n+2)/2) with Hankel transform Floor((n+2)/2)*(cos(pi*n/2)+sin(pi*n/2)). 1
1, 2, 5, 11, 24, 51, 108, 226, 472, 979, 2028, 4182, 8616, 17694, 36312, 74340, 152112, 310659, 634188, 1292686, 2633992, 5360362, 10905480, 22163676, 45032784, 91417646, 185539448, 376279196 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Transform of Floor((n+2)/2)=1,1,2,2,3,3,4,4,...(A008619) under the array A134388. Hankel transform is the signed version of A008619 given by 1,1,-2,-2,3,3,-4,4,....

LINKS

Table of n, a(n) for n=0..27.

FORMULA

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

Conjecture: (n-1)*a(n) -2*n*a(n-1) +4*(4-n)*a(n-2) +8*(n-3)*a(n-3)=0. - R. J. Mathar, Oct 25 2012

CROSSREFS

Sequence in context: A090764 A182557 A027934 * A286945 A111297 A077864

Adjacent sequences:  A134386 A134387 A134388 * A134390 A134391 A134392

KEYWORD

easy,nonn

AUTHOR

Paul Barry, Oct 23 2007

STATUS

approved

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Last modified November 21 00:09 EST 2019. Contains 329348 sequences. (Running on oeis4.)