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A211707 Rectangular array: R(n,k)=n+[n/2+1/2]+...+[n/k+1/2], where [ ]=floor and k>=1, by antidiagonals. 0

%I #7 Jul 12 2012 00:40:01

%S 1,2,2,3,3,2,4,5,4,2,5,6,6,5,2,6,8,7,7,5,2,7,9,10,8,8,5,2,8,11,11,11,

%T 9,9,5,2,9,12,13,13,12,10,9,5,2,10,14,15,15,14,13,11,9,5,2,11,15,17,

%U 17,16,15,14,12,9,5,2,12,17,18,19,19,17,16,15,12,9,5,2,13,18,21

%N Rectangular array: R(n,k)=n+[n/2+1/2]+...+[n/k+1/2], where [ ]=floor and k>=1, by antidiagonals.

%C Limit of n-th row: A056549=(2,5,9,12,17,21,25,...).

%C Row 1: A000027

%C Row 2: A007494

%C R(n,n)=A077024(n)

%C For n>=1, row n is a homogeneous linear recurrence sequence of order A005728(n) with palindromic recurrence coefficients in the sense described at A211701.

%e Northwest corner:

%e 1...2...3...4...5....6....7

%e 2...3...5...6...8....9....11

%e 2...4...6...7...10...11...12

%e 2...5...7...8...11...13...15

%e 2...5...8...9...12...14...16

%t f[n_, m_] := Sum[Floor[n/k + 1/2], {k, 1, m}]

%t TableForm[Table[f[n, m], {m, 1, 20}, {n, 1, 16}]]

%Y Cf. A211701

%K nonn,tabl

%O 1,2

%A _Clark Kimberling_, Apr 20 2012

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Last modified July 31 12:02 EDT 2024. Contains 374800 sequences. (Running on oeis4.)