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 A100551 #14 Mar 27 2023 05:16:33 %S A100551 1,2,-2,3,-8,4,4,-20,24,-8,5,-40,84,-64,16,6,-70,224,-288,160,-32,7, %T A100551 -112,504,-960,880,-384,64,8,-168,1008,-2640,3520,-2496,896,-128,9, %U A100551 -240,1848,-6336,11440,-11648,6720,-2048,256,10,-330,3168,-13728,32032,-43680,35840,-17408,4608,-512 %N A100551 Coefficient list of ChebyshevU(n, 1-x). %H A100551 G. C. Greubel, <a href="/A100551/b100551.txt">Rows n = 0..50 of the triangle, flattened</a> %H A100551 <a href="/index/Ch#Cheby">Index entries for sequences related to Chebyshev polynomials.</a> %F A100551 G.f.: ChebyshevU(n, 1-x). %F A100551 From _G. C. Greubel_, Mar 27 2023: (Start) %F A100551 T(n, k) = binomial(n+k+1, n-k)*(-2)^k. %F A100551 T(n, n) = A122803(n). %F A100551 T(n, n-1) = 2*(-1)^(n-1)*A001787(n), n >= 1. %F A100551 Sum_{k=0..n} T(n, k) = A056594(n). %F A100551 Sum_{k=0..n} (-1)^k*T(n, k) = A001353(n+1). (End) %e A100551 Triangle begins as: %e A100551 1; %e A100551 2, -2; %e A100551 3, -8, 4; %e A100551 4, -20, 24, -8; %e A100551 5, -40, 84, -64, 16; %e A100551 6, -70, 224, -288, 160, -32; %e A100551 7, -112, 504, -960, 880, -384, 64; %e A100551 8, -168, 1008, -2640, 3520, -2496, 896, -128; %e A100551 9, -240, 1848, -6336, 11440, -11648, 6720, -2048, 256; %t A100551 Table[CoefficientList[ChebyshevU[n, 1-x], x], {n, 0, 12}] %o A100551 (PARI) row(n) = Vecrev(polchebyshev(n, 2, 1-x)); \\ _Michel Marcus_, Apr 27 2020 %o A100551 (Magma) [Binomial(n+k+1, n-k)*(-2)^k: k in [0..n], n in [0..12]]; // _G. C. Greubel_, Mar 27 2023 %o A100551 (SageMath) %o A100551 def A100551(n,k): return binomial(n+k+1, n-k)*(-2)^k %o A100551 flatten([[A100551(n,k) for k in range(n+1)] for n in range(13)]) # _G. C. Greubel_, Mar 27 2023 %Y A100551 Cf. A001353, A001787, A053117, A056594, A122803. %K A100551 easy,sign,tabl %O A100551 0,2 %A A100551 _Wouter Meeussen_, Nov 27 2004 %E A100551 Keyword tabl from _Michel Marcus_, Apr 27 2020