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 A086263 #35 May 09 2025 07:14:12
%S A086263 2,14,21,33,34,38,57,85,86,93,94,118,122,133,141,142,145,158,177,201,
%T A086263 202,205,213,214,217,218,230,253,285,298,301,302,326,334,381,393,394,
%U A086263 429,434,445,446,453,481,501,514,526,537,542,553,565,609,622,633,634
%N A086263 Smaller of two consecutive squarefree numbers having equal numbers of prime factors.
%C A086263 a(k) is a term of A075039 iff a(k)+1 = a(k+1).
%C A086263 If a prime divides a(n) then it does not divide a(n) + 1. If a prime divides a(n) + 1, then it does not divide a(n). The sets of prime divisors of a(n) and a(n) + 1 are disjoint. - _Torlach Rush_, Jan 13 2018
%H A086263 Amiram Eldar, <a href="/A086263/b086263.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..1000 from T. D. Noe)
%F A086263 A001221(a(n)) = A001222(a(n)) = A001221(a(n)+1) = A001222(a(n)+1).
%e A086263 230 = 2*5*23 and 230+1 = 3*7*11, therefore 230 is a term.
%t A086263 Select[Range[2, 634], SquareFreeQ[#] && SquareFreeQ[# + 1] && Length[FactorInteger[#]] == Length[FactorInteger[# + 1]] &] (* _T. D. Noe_, Jun 26 2013 *)
%t A086263 #[[1,1]]&/@Select[Partition[Table[{n,If[SquareFreeQ[n],1,0], PrimeOmega[ n]},{n,700}],2,1],#[[1,2]]==#[[2,2]]==1&&#[[1,3]]==#[[2,3]]&] (* _Harvey P. Dale_, Dec 13 2014 *)
%o A086263 (PARI) for(n=1,10^3, if ( issquarefree(n) && issquarefree(n+1) && (omega(n)==omega(n+1)) , print1(n,", "))); \\ _Joerg Arndt_, Jun 26 2013
%Y A086263 Cf. A005117, A263990 (2 prime factors), A215217 (3 prime factors), A318896 (4 prime factors), A318964 (5 prime factors), A001221, A001222, A075039.
%K A086263 nonn
%O A086263 1,1
%A A086263 _Reinhard Zumkeller_, Jul 14 2003