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 A065090 #28 Aug 29 2025 12:23:54
%S A065090 1,2,4,6,8,9,10,12,14,15,16,18,20,21,22,24,25,26,27,28,30,32,33,34,35,
%T A065090 36,38,39,40,42,44,45,46,48,49,50,51,52,54,55,56,57,58,60,62,63,64,65,
%U A065090 66,68,69,70,72,74,75,76,77,78,80,81,82,84,85,86,87,88,90,91,92,93,94
%N A065090 Natural numbers which are not odd primes: composites plus 1 and 2.
%H A065090 Harry J. Smith, <a href="/A065090/b065090.txt">Table of n, a(n) for n = 1..1000</a>
%F A065090 A151763(a(n)) = 0.
%t A065090 Join[{1, 2}, Select[Range[4, 100], CompositeQ]] (* _Paolo Xausa_, Aug 29 2025 *)
%o A065090 (PARI) { n=0; for (m=1, 10^9, if (!isprime(m) || m==2, write("b065090.txt", n++, " ", m); if (n==1000, return)) ) } \\ _Harry J. Smith_, Oct 06 2009
%o A065090 (Haskell)
%o A065090 import Data.List (elemIndices)
%o A065090 a065090 n = a065090_list !! (n-1)
%o A065090 a065090_list = map (+ 1) $ elemIndices 0 a151763_list
%o A065090 -- _Reinhard Zumkeller_, Oct 06 2011
%o A065090 (Python)
%o A065090 from sympy import composite
%o A065090 def A065090(n): return composite(n-2) if n>2 else n # _Chai Wah Wu_, Jul 13 2024
%Y A065090 Cf. A002808, A006005.
%Y A065090 Complement of A065091.
%K A065090 nonn,easy,changed
%O A065090 1,2
%A A065090 _Labos Elemer_, Nov 12 2001