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 A070268 #20 Jul 25 2025 06:56:56
%S A070268 29,41,101,137,229,281,429,433,617,641,645,741,821,969,1021,1085,1129,
%T A070268 1221,1309,1433,1489,1581,1597,1605,1613,1697,1741,1877,1885,2013,
%U A070268 2053,2081,2085,2109,2161,2237,2265,2309,2337,2377,2381,2397,2409,2633,2657,2665,2677
%N A070268 Numbers k such that mu(k) + mu(k+1) + mu(k+2) = -3.
%C A070268 All terms == 1 (mod 4). - _Robert Israel_, Feb 17 2019
%H A070268 Robert Israel, <a href="/A070268/b070268.txt">Table of n, a(n) for n = 1..10000</a>
%p A070268 with(numtheory): A070268:=n->`if`(mobius(n)+mobius(n+1)+mobius(n+2)=-3, n, NULL): seq(A070268(n), n=1..10^4); # _Wesley Ivan Hurt_, Feb 05 2017
%t A070268 seq[max_] := Module[{t = Table[MoebiusMu[n], {n, 1, max}]}, Flatten[Position[Partition[t, 3, 1], _?(Total[#] == -3 &)]]]; seq[2700] (* _Amiram Eldar_, Jul 25 2025 *)
%o A070268 (PARI) isok(n) = moebius(n)+moebius(n+1)+moebius(n+2)==-3;
%Y A070268 Cf. A008683 (mu), A063838.
%K A070268 nonn
%O A070268 1,1
%A A070268 Sharon Sela (sharonsela(AT)hotmail.com), May 09 2002
%E A070268 More terms from _Benoit Cloitre_, May 13 2002