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 A117354 #5 Dec 29 2023 12:54:15 %S A117354 1,-2,1,-2,-1,1,-6,-1,0,1,-22,-3,1,1,1,-90,-11,4,4,2,1,-394,-45,17,16, %T A117354 8,3,1,-1806,-197,76,69,34,13,4,1,-8558,-903,353,313,153,59,19,5,1, %U A117354 -41586,-4279,1688,1472,716,278,92,26,6,1,-206098,-20793,8257,7112,3448,1346,454,134,34 %N A117354 Riordan array ((1-x+sqrt(1-6x+x^2))/2, (1+x-sqrt(1-6x+x^2))/4). %C A117354 First column is A085403. Row sums are A086456. Inverse of A117352. %e A117354 Triangle begins %e A117354 1, %e A117354 -2, 1, %e A117354 -2, -1, 1, %e A117354 -6, -1, 0, 1, %e A117354 -22, -3, 1, 1, 1, %e A117354 -90, -11, 4, 4, 2, 1, %e A117354 -394, -45, 17, 16, 8, 3, 1 %K A117354 easy,sign,tabl %O A117354 0,2 %A A117354 _Paul Barry_, Mar 09 2006