This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A174719 #9 Feb 09 2021 21:40:00 %S A174719 1,1,1,1,-7,1,1,-51,-51,1,1,-239,-399,-239,1,1,-967,-2177,-2177,-967, %T A174719 1,1,-3639,-10191,-13831,-10191,-3639,1,1,-13115,-43719,-74323,-74323, %U A174719 -43719,-13115,1,1,-45919,-177119,-360799,-452639,-360799,-177119,-45919,1 %N A174719 Triangle T(n, k, q) = (1-q^n)*( binomial(n, k) - 1 ) + 1, with q = 3, read by rows. %C A174719 The row sums of this class of sequences, for varying q, is given by Sum_{k=0..n} T(n, k, q) = q^n * (n+1) + 2^n * (1 - q^n). - _G. C. Greubel_, Feb 09 2021 %H A174719 G. C. Greubel, <a href="/A174719/b174719.txt">Rows n = 0..100 of the triangle, flattened</a> %F A174719 T(n, k, q) = (1-q^n)*( binomial(n, k) - 1 ) + 1, with q=3. %F A174719 Sum_{k=0..n} T(n, k, 3) = 3^n*(n+1) + 2^n*(1 - 3^n) = A027471(n+2) - A248216(n). - _G. C. Greubel_, Feb 09 2021 %e A174719 Triangle begins as: %e A174719 1; %e A174719 1, 1; %e A174719 1, -7, 1; %e A174719 1, -51, -51, 1; %e A174719 1, -239, -399, -239, 1; %e A174719 1, -967, -2177, -2177, -967, 1; %e A174719 1, -3639, -10191, -13831, -10191, -3639, 1; %e A174719 1, -13115, -43719, -74323, -74323, -43719, -13115, 1; %e A174719 1, -45919, -177119, -360799, -452639, -360799, -177119, -45919, 1; %t A174719 T[n_, k_, q_]:= 1 +(1-q^n)*(Binomial[n, k] -1); %t A174719 Table[T[n,k,3], {n,0,12}, {k,0,n}]//Flatten %o A174719 (Sage) %o A174719 def T(n,k,q): return 1 + (1-q^n)*(binomial(n,k) - 1) %o A174719 flatten([[T(n,k,3) for k in (0..n)] for n in (0..12)]) # _G. C. Greubel_, Feb 09 2021 %o A174719 (Magma) %o A174719 T:= func< n,k,q | 1 + (1-q^n)*(Binomial(n,k) -1) >; %o A174719 [T(n,k,3): k in [0..n], n in [0..12]]; // _G. C. Greubel_, Feb 09 2021 %Y A174719 Cf. A000012 (q=1), A174718 (q=2), this sequence (q=3), A174720 (q=4). %Y A174719 Cf. A027471, A248216. %K A174719 sign,tabl %O A174719 0,5 %A A174719 _Roger L. Bagula_, Mar 28 2010 %E A174719 Edited by _G. C. Greubel_, Feb 09 2021