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A215630 Triangle read by rows: T(n,k) = n^2 - n*k + k^2, 1 <= k <= n.

%I A215630 #9 Mar 19 2014 12:01:26
%S A215630 1,3,4,7,7,9,13,12,13,16,21,19,19,21,25,31,28,27,28,31,36,43,39,37,37,
%T A215630 39,43,49,57,52,49,48,49,52,57,64,73,67,63,61,61,63,67,73,81,91,84,79,
%U A215630 76,75,76,79,84,91,100,111,103,97,93,91,91,93,97,103,111
%N A215630 Triangle read by rows: T(n,k) = n^2 - n*k + k^2, 1 <= k <= n.
%C A215630 T(n,k) = A093995(n,k) - A075362(n,k) + A133819(n,k) = 2*A070216(n,k) - A215631(n,k), 1 <= k <= n.
%H A215630 Reinhard Zumkeller, <a href="/A215630/b215630.txt">Rows n = 1..120 of triangle, flattened</a>
%e A215630 The triangle begins:
%e A215630 .  1:     1
%e A215630 .  2:     3    4
%e A215630 .  3:     7    7    9
%e A215630 .  4:    13   12   13   16
%e A215630 .  5:    21   19   19   21   25
%e A215630 .  6:    31   28   27   28   31   36
%e A215630 .  7:    43   39   37   37   39   43   49
%e A215630 .  8:    57   52   49   48   49   52   57   64
%e A215630 .  9:    73   67   63   61   61   63   67   73   81
%e A215630 . 10:    91   84   79   76   75   76   79   84   91  100
%e A215630 . 11:   111  103   97   93   91   91   93   97  103  111  121
%e A215630 . 12:   133  124  117  112  109  108  109  112  117  124  133  144 .
%o A215630 (Haskell)
%o A215630 a215630 n k = a215630_tabl !! (n-1) !! (k-1)
%o A215630 a215630_row n = a215630_tabl !! (n-1)
%o A215630 a215630_tabl = zipWith3 (zipWith3 (\u v w -> u - v + w))
%o A215630                         a093995_tabl a075362_tabl a133819_tabl
%Y A215630 Cf. A004068 (row sums), A002061 (left edge), A000290 (right edge).
%Y A215630 Cf. A003215 (central terms).
%K A215630 nonn,tabl
%O A215630 1,2
%A A215630 _Reinhard Zumkeller_, Nov 11 2012