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A109593 Sequence and first differences include all odd numbers exactly once. 1

%I

%S 1,4,9,16,27,40,55,72,91,112,135,160,189,220,253,288,325,364,405,448,

%T 493,540,589,640,693,750,809,870,933,998,1065,1134,1205,1278,1353,

%U 1430,1509,1590,1673,1758,1845,1934,2027,2122,2219,2318,2419,2522,2627,2734

%N Sequence and first differences include all odd numbers exactly once.

%C See A005228.

%H Alois P. Heinz, <a href="/A109593/b109593.txt">Table of n, a(n) for n = 1..1000</a>

%F a(n) = n^2 + C*n^(3/2) + O(n), where C = 5/6. According to the simplified model: the sum of n consecutive odd numbers without the odd squares. - _Thomas Ordowski_, Sep 24 2014

%t a = {1}; d = 3; k = 1; Do[ While[ Position[a, d] != {}, d += 2 ]; k = k + d; d += 2; a = Append[a, k], {n, 49} ]; a (* _Robert G. Wilson v_, Sep 28 2005 *)

%Y Cf. A005228.

%K base,easy,nonn

%O 1,2

%A _Eric Angelini_, Aug 30 2005

%E Corrected and extended by _Robert G. Wilson v_, Sep 28 2005

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Last modified February 5 03:48 EST 2023. Contains 360082 sequences. (Running on oeis4.)