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 A347227 #18 Aug 25 2021 07:42:18 %S A347227 1,1,-2,1,-3,-2,1,-5,-4,1,1,-9,-10,2,-2,1,-17,-28,4,-6,4,1,-33,-82,8, %T A347227 -26,12,-2,1,-65,-244,16,-126,50,-8,0,1,-129,-730,32,-626,252,-50,0,1, %U A347227 1,-257,-2188,64,-3126,1394,-344,0,3,4,1,-513,-6562,128,-15626,8052,-2402,0,9,18,-2 %N A347227 Square array T(n,k), n >= 1, k >= 0, read by antidiagonals downwards, where T(n,k) = Sum_{d|n} mu(d)*mu(n/d)*d^k. %H A347227 Seiichi Manyama, <a href="/A347227/b347227.txt">Antidiagonals n = 1..140, flattened</a> %F A347227 Dirichlet g.f. of column k: 1/(zeta(s)*zeta(s-k)). %e A347227 Square array begins: %e A347227 1, 1, 1, 1, 1, 1, ... %e A347227 -2, -3, -5, -9, -17, -33, ... %e A347227 -2, -4, -10, -28, -82, -244, ... %e A347227 1, 2, 4, 8, 16, 32, ... %e A347227 -2, -6, -26, -126, -626, -3126, ... %e A347227 4, 12, 50, 252, 1394, 8052, ... %t A347227 T[n_, k_] := DivisorSum[n, MoebiusMu[#] * MoebiusMu[n/#] * #^k &]; Table[T[n - k + 1, k], {n, 0, 10}, {k, n, 0, -1}] // Flatten (* _Amiram Eldar_, Aug 24 2021 *) %o A347227 (PARI) T(n, k) = sumdiv(n, d, moebius(d)*moebius(n/d)*d^k); %Y A347227 Columns k=0..5 give A007427, A046692, A053822, A053825, A053826, A178448. %Y A347227 T(n,n) gives A347251. %K A347227 sign,tabl %O A347227 1,3 %A A347227 _Seiichi Manyama_, Aug 24 2021