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 A089495 #8 Feb 16 2025 08:32:51
%S A089495 -1,0,1,0,0,1,0,0,0,-1,0,1,-1,0,0,0,0,1,0,0,1,0,0,0,0,-1,0,0,-1,-1,0,
%T A089495 0,-1,0,0,0,1,0,0,-1,0,-1,0,1,0,0,0,0,0,-1,0,0,0,0,-1,0,0,0,1,-1,0,0,
%U A089495 0,0,1,-1,0,0,0,0,-1,0,0,-1,0,0,1,1,-1,-1,0,1,0,-1,0,0,0,1,1,0,0,0,0,0,0,0,1,0,0,1,0,0,0,1,0,0,0,0,0,-1,0,1,-1,0,0,-1,0,0
%N A089495 a(n) = mu(prime(n)+1), where mu is the Moebius function.
%H A089495 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/MoebiusFunction.html">Moebius Function</a>
%t A089495 Table[MoebiusMu[Prime[n]+1], {n, 150}]
%Y A089495 Cf. A049098 (primes p such that mu(p+1) = 0), A078329 (primes p such that mu(p+1) = -1), A089523 (primes p such that mu(p+1) = 1), A089451 (mu(p-1) for prime p), A089496 (mu(p+1)+mu(p-1) for prime p), A089497 (mu(p+1)-mu(p-1) for prime p).
%Y A089495 A067461(n) - 1.
%K A089495 sign
%O A089495 1,1
%A A089495 _T. D. Noe_, Nov 04 2003