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 A178346 #12 Oct 06 2024 09:44:37 %S A178346 1,1,1,1,5,1,1,18,18,1,1,52,144,52,1,1,131,766,766,131,1,1,303,3273, %T A178346 6743,3273,303,1,1,664,12312,45422,45422,12312,664,1,1,1406,42844, %U A178346 261230,463348,261230,42844,1406,1,1,2913,141936,1358100,3915312,3915312,1358100,141936,2913,1,1,5953,455481,6595734,29172972,47114784,29172972,6595734,455481,5953,1 %N A178346 Triangle read by rows: T(n, k, m) = binomial(n, k) - m*binomial(n, k)*binomial(n+1, k)/(k+1) + m*A008292(n+1, k+1) with m = 3. %H A178346 G. C. Greubel, <a href="/A178346/b178346.txt">Rows n = 0..50 of the triangle, flattened</a> %F A178346 T(n, k, m) = binomial(n, k) - m*binomial(n, k)*binomial(n+1, k)/(k+1) + m*Eulerian(n+1, k+1) with m = 3, and Eulerian(n,k) = A008292(n,k). %F A178346 Sum_{k=0..n} T(n, k) = 2^n + 3*(n+1)! - 3*Catalan(n+1) = 2^n + 3*A056986(n+1). - _G. C. Greubel_, Oct 05 2024 %e A178346 Triangle begins as: %e A178346 1; %e A178346 1, 1; %e A178346 1, 5, 1; %e A178346 1, 18, 18, 1; %e A178346 1, 52, 144, 52, 1; %e A178346 1, 131, 766, 766, 131, 1; %e A178346 1, 303, 3273, 6743, 3273, 303, 1; %e A178346 1, 664, 12312, 45422, 45422, 12312, 664, 1; %e A178346 1, 1406, 42844, 261230, 463348, 261230, 42844, 1406, 1; %e A178346 1, 2913, 141936, 1358100, 3915312, 3915312, 1358100, 141936, 2913, 1; %t A178346 EulerianNumber[n_, k_] := EulerianNumber[n, k] = Sum[(-1)^j*(k-j)^n*Binomial[n+ 1, j], {j,0,k}]; %t A178346 A178346[n_, k_, m_]:= Binomial[n, k] - m*Binomial[n, k]*Binomial[n+1, k]/(k+1) + m*EulerianNumber[n+1, k+1]; %t A178346 Table[A178346[n,k,3], {n,0,15}, {k,0,n}]//Flatten %o A178346 (Magma) %o A178346 A178346:= func< n,k | Binomial(n, k) - 3*(Binomial(n, k)*Binomial(n+1, k)/(k+1)) + 3*EulerianNumber(n+1, k) >; %o A178346 [A178346(n,k): k in [0..n], n in [0..15]]; // _G. C. Greubel_, Oct 05 2024 %o A178346 (SageMath) %o A178346 def A008292(n,k): return sum((-1)^j*binomial(n+1, j)*(k-j)^n for j in (0..k)) %o A178346 def A178346(n,k): return binomial(n,k) - 3*binomial(n,k)*binomial(n+1,k)/(k+1) + 3*A008292(n+1,k+1) %o A178346 flatten([[A178346(n,k) for k in range(n+1)] for n in range(16)]) # _G. C. Greubel_, Oct 05 2024 %Y A178346 Cf. A008292. %K A178346 nonn,tabl %O A178346 0,5 %A A178346 _Roger L. Bagula_, May 25 2010 %E A178346 Edited by _G. C. Greubel_, Oct 05 2024