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A098180 Odd numbers with two times the odd numbers repeated in order between them. 2
1, 2, 2, 3, 5, 6, 6, 7, 9, 10, 10, 11, 13, 14, 14, 15, 17, 18, 18, 19, 21, 22, 22, 23, 25, 26, 26, 27, 29, 30, 30, 31, 33, 34, 34, 35, 37, 38, 38, 39, 41, 42, 42, 43, 45, 46, 46, 47, 49, 50, 50, 51, 53, 54, 54, 55, 57, 58, 58, 59, 61, 62, 62, 63, 65, 66, 66, 67, 69, 70, 70, 71 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

COMMENTS

Partial sums of A098178.

FORMULA

G.f. : (1+x)(1-x+x^2)/((1-x)^2(1+x^2)); a(n)=sqrt(2)*sin(pi*n/2+pi/4)/2+n+1/2, a(n)=2a(n-1)-2a(n-2)+2a(n-3)-a(n-4).

CROSSREFS

Sequence in context: A137756 A051732 A098382 * A117752 A172992 A006065

Adjacent sequences:  A098177 A098178 A098179 * A098181 A098182 A098183

KEYWORD

easy,nonn

AUTHOR

Paul Barry (pbarry(AT)wit.ie), Aug 30 2004

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Last modified February 17 09:41 EST 2012. Contains 206009 sequences.