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 A174295 #6 Nov 26 2021 06:07:32 %S A174295 1,-1,1,-1,0,1,0,-1,0,1,-1,0,0,0,1,1,-2,-1,1,0,1,-3,2,0,-2,2,0,1,6,-7, %T A174295 -3,3,-3,3,0,1,-15,14,3,-10,7,-4,4,0,1,36,-37,-12,19,-19,12,-5,5,0,1, %U A174295 -91,90,24,-54,42,-30,18,-6,6,0,1,232,-233,-67,127,-115,73,-43,25,-7,7 %N A174295 Matrix inverse of A174294. %C A174295 First column is a signed version of A099323 with an additional leading 1. %C A174295 First 5 rows as in A054525. %H A174295 G. C. Greubel, <a href="/A174295/b174295.txt">Rows n = 0..50 of the triangle, flattened</a> %F A174295 Sum_{k=0..n} T(n, k) = A000007(n). %F A174295 T(n, 0) = A174297(n). %e A174295 Table begins: %e A174295 n\k|...0...1...2...3...4...5...6...7...8...9..10 %e A174295 ---|-------------------------------------------- %e A174295 0..|...1 %e A174295 1..|..-1...1 %e A174295 2..|..-1...0...1 %e A174295 3..|...0..-1...0...1 %e A174295 4..|..-1...0...0...0...1 %e A174295 5..|...1..-2..-1...1...0...1 %e A174295 6..|..-3...2...0..-2...2...0...1 %e A174295 7..|...6..-7..-3...3..-3...3...0...1 %e A174295 8..|.-15..14...3.-10...7..-4...4...0...1 %e A174295 9..|..36.-37.-12..19.-19..12..-5...5...0...1 %e A174295 10.|.-91..90..24.-54..42.-30..18..-6...6...0...1 %t A174295 t[n_, k_]:= t[n, k]= If[k<0 || k>n, 0, If[k==0 || k==n, 1, If[k==1, Mod[n, 2], t[n-1, k-1] +t[n-2, k-1] -t[n-1, k] -t[n-2, k] ]]]; (* t = A174294 *) %t A174295 M:= With[{m=30}, Table[t[n, k], {n,0,m}, {k,0,m}]]; %t A174295 T:= Inverse[M]; %t A174295 Table[T[[n+1, k+1]], {n,0,15}, {k,0,n}]//Flatten (* _G. C. Greubel_, Nov 25 2021 *) %Y A174295 Cf. A000007 (row sums), A054525, A099323, A112467, A112468, A174294, A174296, A174297. %K A174295 sign,tabl %O A174295 0,17 %A A174295 _Mats Granvik_, Mar 15 2010