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A173039 Odd numerators of the fractions (1/4-1/n^2), n>= -2. 2
-3, -1, -3, 5, 3, 21, 45, 15, 77, 117, 35, 165, 221, 63, 285, 357, 99, 437, 525, 143, 621, 725, 195, 837, 957, 255, 1085, 1221, 323, 1365, 1517, 399, 1677, 1845, 483, 2021, 2205, 575, 2397, 2597, 675 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Odd numbers in A061037, which is extended to negative n, and uses -1 to represent -1/0 at n=0. Trisections are apparently A003185, A000466 and A085027.

LINKS

Table of n, a(n) for n=1..41.

FORMULA

Conjecture: a(n)= +3*a(n-3) -3*a(n-6) +a(n-9). G.f.: ( 3+x+3*x^2-14*x^3-6*x^4-30*x^5-21*x^6-3*x^7-5*x^8 ) / ( (x-1)^3*(1+x+x^2)^3 ). - R. J. Mathar, Dec 02 2010

CROSSREFS

Sequence in context: A012264 A063198 A122582 * A016471 A324294 A082082

Adjacent sequences:  A173036 A173037 A173038 * A173040 A173041 A173042

KEYWORD

sign

AUTHOR

Paul Curtz, Nov 21 2010

STATUS

approved

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Last modified February 27 22:31 EST 2020. Contains 332312 sequences. (Running on oeis4.)