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 A023579 #16 Sep 08 2022 08:44:47
%S A023579 0,1,3,1,1,4,2,1,1,5,1,3,2,1,1,3,1,6,1,1,2,1,1,2,2,3,1,1,4,2,1,1,2,1,
%T A023579 3,1,5,1,1,4,1,3,1,2,3,1,1,1,1,3,2,1,2,1,2,1,4,1,3,2,1,3,1,1,2,6,1,2,
%U A023579 1,5,2,1,1,3,1,1,3,4,2,2,1,3,1,2,1,1,2,2,4,1,1,1,1,1,1,1,9,2,1
%N A023579 Exponent of 2 in prime factorization of prime(n)+3.
%H A023579 G. C. Greubel, <a href="/A023579/b023579.txt">Table of n, a(n) for n = 1..10000</a>
%F A023579 a(n) = A007814(A113935(n)). - _Michel Marcus_, Sep 30 2013
%e A023579 For n=1, prime(1)+3=5, and 5 is odd, so a(1)=0.
%t A023579 Table[IntegerExponent[3 + Prime[n], 2], {n, 100}] (* _G. C. Greubel_, May 21 2019 *)
%o A023579 (PARI) a(n) = valuation(prime(n)+3, 2); \\ _Michel Marcus_, Sep 30 2013
%o A023579 (Magma) [Valuation(3+NthPrime(n), 2): n in [1..100]]; // _G. C. Greubel_, May 21 2019
%o A023579 (Sage) [(nth_prime(n)+3).valuation(2) for n in (1..100)] # _G. C. Greubel_, May 21 2019
%o A023579 (Python)
%o A023579 from sympy import prime
%o A023579 def A023579(n): return (~(m:=prime(n)+3)& m-1).bit_length() # _Chai Wah Wu_, Jul 07 2022
%K A023579 nonn
%O A023579 1,3
%A A023579 _Clark Kimberling_
%E A023579 a(1) corrected by _Michel Marcus_, Sep 30 2013
%E A023579 Name corrected by _Charles R Greathouse IV_, Mar 31 2014