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A210978 A186029 and positive terms of A001106 interleaved. 6
0, 1, 5, 9, 17, 24, 36, 46, 62, 75, 95, 111, 135, 154, 182, 204, 236, 261, 297, 325, 365, 396, 440, 474, 522, 559, 611, 651, 707, 750, 810, 856, 920, 969, 1037, 1089, 1161, 1216, 1292, 1350, 1430, 1491, 1575, 1639, 1727, 1794, 1886, 1956, 2052, 2125, 2225, 2301 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
COMMENTS
Vertex number of a square spiral similar to A118277.
LINKS
FORMULA
a(n) = (3*(-1+(-1)^n)+2*(5+(-1)^n)*n+14*n^2)/16. a(n) = a(n-1)+2*a(n-2)-2*a(n-3)-a(n-4)+a(n-5). G.f.: -x*(2*x^2+4*x+1) / ((x-1)^3*(x+1)^2). - Colin Barker, Sep 15 2013
PROG
(PARI) Vec(-x*(2*x^2+4*x+1)/((x-1)^3*(x+1)^2) + O(x^100)) \\ Colin Barker, Sep 15 2013
CROSSREFS
Members of this family are A093005, A210977, A006578, this sequence, A181995, A210981, A210982.
Sequence in context: A276194 A157970 A054278 * A211434 A182388 A080335
KEYWORD
nonn,easy
AUTHOR
Omar E. Pol, Aug 03 2012
EXTENSIONS
More terms from Colin Barker, Sep 15 2013
STATUS
approved

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Last modified February 23 01:54 EST 2024. Contains 370265 sequences. (Running on oeis4.)