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 A120911 Triangle read by rows where t(n,m) is the (floor(n/m))th integer from among those positive integers not occurring earlier in the sequence. 3

%I

%S 1,3,2,6,4,5,10,8,7,9,15,12,11,13,14,21,18,17,16,19,20,28,24,23,22,25,

%T 26,27,36,32,30,31,29,33,34,35,45,40,39,38,37,41,42,43,44,55,50,48,47,

%U 49,46,51,52,53,54,66,60,58,57,59,56,61,62,63,64,65,78,72,70,69,68,71

%N Triangle read by rows where t(n,m) is the (floor(n/m))th integer from among those positive integers not occurring earlier in the sequence.

%H Ivan Neretin, <a href="/A120911/b120911.txt">Table of n, a(n) for n = 1..5050</a>

%F T(n,k) = n(n-1)/2 + U(n,k), where U(n,1) = n, U(n,k) = k-1 if floor(n/k) = floor(n/(k-1)), otherwise U(n,k) = floor(n/k). - _Franklin T. Adams-Watters_, Jul 25 2006

%t a = {1}; Do[r = Quotient[n, k]; AppendTo[a, Complement[Range[Max@a + r + 1], a][[r]]], {n, 2, 12}, {k, n}]; a (* _Ivan Neretin_, Dec 15 2016 *)

%Y Cf. A120912, A120913.

%K easy,nonn,tabl

%O 1,2

%A _Leroy Quet_, Jul 15 2006

%E More terms from _Franklin T. Adams-Watters_, Jul 25 2006

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Last modified December 5 06:52 EST 2021. Contains 349543 sequences. (Running on oeis4.)