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 A262095 #25 Oct 13 2018 09:14:34 %S A262095 1,2,2,2,2,3,2,3,2,3,2,4,2,3,3,4,2,4,2,4,3,3,2,6,2,3,3,4,2,5,2,5,3,3, %T A262095 3,6,2,3,3,6,2,5,2,4,4,3,2,8,2,4,3,4,2,6,3,6,3,3,2,8,2,3,4,6,3,5,2,4, %U A262095 3,5,2,9,2,3,4,4,3,5,2,8,4,3,2,8,3,3,3,6,2,8,3,4,3,3,3,10,2 %N A262095 Number of non-semiprime divisors of n. %H A262095 Charles R Greathouse IV, <a href="/A262095/b262095.txt">Table of n, a(n) for n = 1..10000</a> %F A262095 a(n) = A000005(n) - A086971(n). %F A262095 A083399(n) <= a(n) <= A000005(n). %F A262095 a(n) = Sum_{k=1..A000005(n)} (1 - A064911(A027750(n,k))). - _Reinhard Zumkeller_, Sep 14 2015 %e A262095 (1, 2, 3, 4, 6, 8, 12, 24) are the divisors of n = 24: 1, 2, 3, 8, 12, and 24 are non-semiprimes, therefore a(24) = 6. %t A262095 Table[Count[Divisors@ n, x_ /; PrimeOmega@ x != 2], {n, 97}] (* _Michael De Vlieger_, Sep 14 2015 *) %o A262095 (PARI) a(n) = sumdiv(n, d, bigomega(d)!=2); \\ _Michel Marcus_, Sep 11 2015 %o A262095 (PARI) a(n)=my(f=factor(n)[,2]); prod(i=1,#f,f[i]+1) - sum(i=1,#f,f[i]>1) - #f*(#f-1)/2 \\ _Charles R Greathouse IV_, Sep 14 2015 %o A262095 (Haskell) %o A262095 a262095 = sum . map ((1 -) . a064911) . a027750_row %o A262095 -- _Reinhard Zumkeller_, Sep 14 2015 %Y A262095 Cf. A000005, A083399, A086971, A100959. %Y A262095 Cf. A064911, A027750. %K A262095 nonn,easy %O A262095 1,2 %A A262095 _Juri-Stepan Gerasimov_, Sep 11 2015