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 A378122 #5 Nov 20 2024 09:50:56 %S A378122 1,1,2,1,2,1,2,2,2,2,2,1,3,1,2,2,3,2,2,2,2,2,3,2,3,2,2,2,3,2,3,2,3,2, %T A378122 2,2,3,2,3,2,3,2,3,2,3,2,3,2,3,3,3,2,4,2,2,3,4,2,2,1,3,2,3,1,2,2,3,3, %U A378122 3,3,3,2,3,2,2,3,4,2,3,3,2,2,2,4,3,3 %N A378122 a(n) = number of prime divisors of the sum of the first n primes. %e A378122 2+3+5+7+11 = 28 = 2*2*7, so a(5) = 2. %t A378122 a[n_] := PrimeNu[Total[Prime[Range[n]]]]; Array[a, 500] %Y A378122 Cf. A000040, A071215, A008334, A008335, A378123. %K A378122 nonn %O A378122 1,3 %A A378122 _Clark Kimberling_, Nov 17 2024