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 A053858 #15 May 21 2024 14:14:36 %S A053858 30,42,66,70,78,102,110,114,130,138,154,170,174,182,186,190,222,230, %T A053858 238,246,258,266,282,286,290,310,318,322,354,366,370,374,402,406,410, %U A053858 418,426,430,434,438,442,470,474,494,498,506,518,530,534,574,582,590 %N A053858 Squarefree even composite numbers with an odd number of prime factors. %C A053858 Prime factors counted with multiplicity. - _Harvey P. Dale_, May 21 2024 %H A053858 Charles R Greathouse IV, <a href="/A053858/b053858.txt">Table of n, a(n) for n = 1..10000</a> %e A053858 a(3)=66 because 66 is even and its prime divisors are 2, 3 and 11, an odd number. %p A053858 ts_m2_sod := proc(n); if (numtheory[mobius](n)=-1 and isprime(n)='false' and type(n,even)='true') then RETURN(n); fi end: am2sod := [seq(ts_m2_sod(i), i=1..2500)]: am2sod; %t A053858 Select[Range[2,602,2],CompositeQ[#]&&SquareFreeQ[#]&&OddQ[PrimeOmega[#]]&] (* _Harvey P. Dale_, May 21 2024 *) %o A053858 (PARI) is(n,f=factor(n))=n%2==0 && #f[,2]>2 && vecmax(f[,2])==1 && (#f[,2])%2 \\ _Charles R Greathouse IV_, Aug 29 2017 %Y A053858 A075819 is a subsequence. Intersection of A026424, A039956, and A002808. %K A053858 easy,nonn %O A053858 1,1 %A A053858 _Enoch Haga_, Mar 28 2000 %E A053858 Name corrected by _Charles R Greathouse IV_, Aug 29 2017