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 A025561 #8 Jan 20 2024 17:44:44
%S A025561 0,0,1,1,3,3,4,4,6,6,7,7,8,8,9,8,10,10,11,11,12,11,12,12,13,13,14,14,
%T A025561 15,15,16,16,18,17,18,17,18,18,19,18,19,19,20,20,21,20,21,21,22,22,23,
%U A025561 22,23,23,24,23,24,23,24,24,25,25,26,25,27,26,27,27,28,27,28,28,29,29,30
%N A025561 a(n) = sum of the exponents in the prime factorization of LCM{1, n-1, ..., C(n-[ n/2 ],[ n/2 ])}.
%F A025561 a(n) = A001222(A025560(n)). - _Sean A. Irvine_, Sep 06 2019
%Y A025561 Cf. A001222, A025560.
%K A025561 nonn
%O A025561 1,5
%A A025561 _Clark Kimberling_
%E A025561 More terms from _Sean A. Irvine_, Sep 06 2019