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 A144405 #6 Mar 27 2021 23:52:25 %S A144405 1,1,1,1,18,1,1,69,69,1,1,172,606,172,1,1,345,2890,2890,345,1,1,606, %T A144405 9885,23580,9885,606,1,1,973,27321,127365,127365,27321,973,1,1,1464, %U A144405 65044,523656,1024030,523656,65044,1464,1,1,2097,138636,1770972,5985126,5985126,1770972,138636,2097,1 %N A144405 Triangle T(n,k) = binomial(n, k)*(3*binomial(n, k)^2 - binomial(n, k) - 1), read by rows. %H A144405 G. C. Greubel, <a href="/A144405/b144405.txt">Rows n = 0..50 of the triangle, flattened</a> %F A144405 T(n,k) = binomial(n, k)*(3*binomial(n, k)^2 - binomial(n, k) - 1). %F A144405 Sum_{k=0..n} T(n, k) = A000172(n) - A000984(n) - 2^n = Hypergeometric3F2([-n, -n, -n], [1, 1], -1) - binomial(2*n, n) - 2^n. - _G. C. Greubel_, Mar 27 2021 %e A144405 Triangle begins as: %e A144405 1; %e A144405 1, 1; %e A144405 1, 18, 1; %e A144405 1, 69, 69, 1; %e A144405 1, 172, 606, 172, 1; %e A144405 1, 345, 2890, 2890, 345, 1; %e A144405 1, 606, 9885, 23580, 9885, 606, 1; %e A144405 1, 973, 27321, 127365, 127365, 27321, 973, 1; %e A144405 1, 1464, 65044, 523656, 1024030, 523656, 65044, 1464, 1; %e A144405 1, 2097, 138636, 1770972, 5985126, 5985126, 1770972, 138636, 2097, 1; %e A144405 1, 2890, 271305, 5169480, 27738690, 47945268, 27738690, 5169480, 271305, 2890, 1; %p A144405 A144405:= (n,k) -> binomial(n, k)*(3*binomial(n, k)^2 - binomial(n, k) - 1); %p A144405 seq(seq( A144405(n,k), k=0..n), n=0..12); # _G. C. Greubel_, Mar 27 2021 %t A144405 Table[Table[Binomial[n, m]*(3*Binomial[n, m]^2 - Binomial[n, m] - 1), {m, 0, n}], {n, 0, 10}]; Flatten[%] %o A144405 (Magma) [Binomial(n, k)*(3*Binomial(n, k)^2 - Binomial(n, k) - 1): k in [0..n], n in [0..12]]; // _G. C. Greubel_, Mar 27 2021 %o A144405 (Sage) flatten([[binomial(n, k)*(3*binomial(n, k)^2 - binomial(n, k) - 1) for k in (0..n)] for n in (0..12)]) # _G. C. Greubel_, Mar 27 2021 %Y A144405 Cf. A000172, A000984, A144404. %K A144405 nonn,tabl %O A144405 0,5 %A A144405 _Roger L. Bagula_ and _Gary W. Adamson_, Oct 03 2008 %E A144405 Edited by _G. C. Greubel_, Mar 27 2021