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A114753
First column of A114751.
7
1, 3, 3, 7, 5, 11, 7, 15, 9, 19, 11, 23, 13, 27, 15, 31, 17, 35, 19, 39, 21, 43, 23, 47, 25, 51, 27, 55, 29, 59, 31, 63, 33, 67, 35, 71, 37, 75, 39, 79, 41, 83, 43, 87, 45, 91, 47, 95, 49, 99, 51, 103, 53, 107, 55, 111, 57, 115, 59, 119, 61, 123, 63, 127, 65, 131, 67, 135, 69
OFFSET
1,2
COMMENTS
A114752, (1, 2, 5, 4, 9, 6, ...) + A114753 - (1,1,1,...) = 3n+1: (1, 4, 7, 10, 13, ...). - Gary W. Adamson, Sep 16 2007
First column of table A210530. - Boris Putievskiy, Jan 29 2013
FORMULA
a(2n+1) = 2n+1, a(2n) = 4n-1.
a(n) = 2*a(n-2) - a(n-4). - Joerg Arndt, Apr 02 2011
Equals A133080 * [1,2,3,...]. - Gary W. Adamson, Sep 08 2007
G.f. x*(1+3*x+x^2+x^3) / ( (x-1)^2*(1+x)^2 ). - R. J. Mathar, Apr 04 2012
a(n) = (3*n-1-(n-1)*(-1)^(n-1))/2. - Boris Putievskiy, Jan 29 2013
MATHEMATICA
Table[If[OddQ[n], n, 2n-1], {n, 1, 120}] (* Vladimir Joseph Stephan Orlovsky, Apr 02 2011*)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Amarnath Murthy, Nov 15 2005
EXTENSIONS
More terms from Joshua Zucker, May 05 2006
STATUS
approved