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 A348127 #10 Mar 02 2022 02:51:47 %S A348127 0,1,1,-1,0,-1,1,-1,-1,-1,2,0,0,-3,0,0,3,-3,-1,-1,4,-4,-1,-5,6,2,2, %T A348127 -17,4,4,13,-16,-7,-11,30,-14,-7,-34,42,7,16,-80,27,6,95,-117,-21,-60, %U A348127 223,-97,-48,-265,326,53,129,-800,242,93,752,-948,-105,-499,1806,-853,-240,-2189,2750,124 %N A348127 Product_{n>=1} 1 / (1 - a(n)*x^n) = 1 + Sum_{n>=1} x^prime(n). %H A348127 Robert Israel, <a href="/A348127/b348127.txt">Table of n, a(n) for n = 1..2500</a> %p A348127 N:= 20: # for a(1)..a(N) %p A348127 P:= 1: a:= Vector(N): %p A348127 for n from 1 to N do %p A348127 c:= coeff(P,x,n); %p A348127 if isprime(n) then a[n]:= 1-c else a[n]:= -c fi; %p A348127 P:= series(P/(1-a[n]*x^n),x,N+1); %p A348127 od: %p A348127 convert(a,list); # _Robert Israel_, Mar 01 2022 %Y A348127 Cf. A000040, A002121, A010051, A030010, A147557, A305871, A305882, A308298, A328777, A348128. %K A348127 sign %O A348127 1,11 %A A348127 _Ilya Gutkovskiy_, Oct 01 2021