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A132728 Triangle T(n, k) = 4 - 3*(-1)^k, read by rows.

%I A132728 #29 Jul 21 2021 12:49:57
%S A132728 1,1,7,1,7,1,1,7,1,7,1,7,1,7,1,1,7,1,7,1,7,1,7,1,7,1,7,1,1,7,1,7,1,7,
%T A132728 1,7,1,7,1,7,1,7,1,7,1,1,7,1,7,1,7,1,7,1,7,1,7,1,7,1,7,1,7,1,7,1
%N A132728 Triangle T(n, k) = 4 - 3*(-1)^k, read by rows.
%H A132728 G. C. Greubel, <a href="/A132728/b132728.txt">Rows n = 0..30 of the triangle, flattened</a>
%F A132728 From _G. C. Greubel_, Feb 14 2021: (Start)
%F A132728 T(n, k) = 4 - 3*(-1)^k.
%F A132728 Sum_{k=0..n} T(n, k) = (8*n + 5 - 3*(-1)^n)/2 = A047393(n+2). (End)
%F A132728 Bivariate g.f.: (1 + 7*x*y)/((1 - x)*(1 - x*y)*(1 + x*y)). - _J. Douglas Morrison_, Jul 19 2021
%e A132728 Triangle begins as:
%e A132728   1;
%e A132728   1, 7;
%e A132728   1, 7, 1;
%e A132728   1, 7, 1, 7;
%e A132728   1, 7, 1, 7, 1;
%e A132728   1, 7, 1, 7, 1, 7;
%e A132728   1, 7, 1, 7, 1, 7, 1;
%e A132728   1, 7, 1, 7, 1, 7, 1, 7;
%e A132728   1, 7, 1, 7, 1, 7, 1, 7, 1;
%e A132728   1, 7, 1, 7, 1, 7, 1, 7, 1, 7;
%e A132728   1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1;
%t A132728 Table[PadRight[{},n,{1,7}],{n,20}]//Flatten (* _Harvey P. Dale_, Aug 02 2019 *)
%t A132728 Table[4 -3*(-1)^k, {n,0,12}, {k,0,n}]//Flatten (* _G. C. Greubel_, Feb 14 2021 *)
%o A132728 (Sage) flatten([[4 -3*(-1)^k for k in (0..n)] for n in (0..12)]) # _G. C. Greubel_, Feb 14 2021
%o A132728 (Magma) [4 -3*(-1)^k: k in [0..n], n in [0..12]]; // _G. C. Greubel_, Feb 14 2021
%Y A132728 Cf. A010688, A047393, A132742.
%K A132728 nonn,easy,tabl,less
%O A132728 0,3
%A A132728 _Roger L. Bagula_, Nov 17 2007
%E A132728 Edited and corrected by _Joerg Arndt_, Dec 26 2018
%E A132728 Offset and title changed by _G. C. Greubel_, Feb 14 2021