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 A382789 #7 Apr 05 2025 09:10:10
%S A382789 0,0,1,3,5,7,10,14,17,19,22,25,29,33,36,38,41,43,47,50,53,58,61,63,67,
%T A382789 73,77,80,82,87,92,96,99,103,106,109,113,117,122,124,127,129,134,137,
%U A382789 144,148,152,156,159,161,165,169,172,178,182,190,192,195,200,204
%N A382789 The number of prime factors of Euler phi of the n-th primorial number, counted with multiplicity.
%H A382789 Amiram Eldar, <a href="/A382789/b382789.txt">Table of n, a(n) for n = 0..10000</a>
%F A382789 a(n) = A001222(A000010(A002110(n))).
%F A382789 a(n) = A001222(A005867(n)).
%F A382789 a(n) = Sum_{k=1..n} A023508(k).
%t A382789 Join[{0}, Accumulate[PrimeOmega[Prime[Range[100]] - 1]]]
%o A382789 (PARI) list(nmax) = {my(s = 0, c = 0); print1(s, ", "); forprime(p = 1, , c++; s += bigomega(p-1); print1(s, ", "); if(c == nmax, break));}
%Y A382789 Partial sums of A023508.
%Y A382789 Cf. A000010, A002110, A001222, A055768, A055769.
%K A382789 nonn,easy
%O A382789 0,4
%A A382789 _Amiram Eldar_, Apr 05 2025