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 A023839 #10 Jun 14 2025 04:18:23
%S A023839 0,2,3,5,6,7,8,9,9,10,10,13,12,15,13,15,15,14,16,18,16,18,19,19,22,23,
%T A023839 23,24,23,23,22,26,22,24,25,24,24,28,26,27,28,27,28,33,30,29,31,33,33,
%U A023839 34,35,38,37,39,37,37,38,38,42,40,38,40,39,41,38,36,38,43,40,44,42,44,42,44,45,48,49,49
%N A023839 Sum of exponents in prime-power factorization of C(5n,n-2).
%H A023839 Ivan Neretin, <a href="/A023839/b023839.txt">Table of n, a(n) for n = 2..10000</a>
%F A023839 From _Amiram Eldar_, Jun 14 2025: (Start)
%F A023839 a(n) = A001222(A004344(n-2)).
%F A023839 a(n) = A023838(n) - A001222(4*n+2) + A001222(n-1). (End)
%t A023839 Table[PrimeOmega[Binomial[5 n, n - 2]], {n, 2, 79}] (* _Ivan Neretin_, Nov 08 2017 *)
%o A023839 (PARI) a(n) = bigomega(binomial(5*n,n-2)); \\ _Amiram Eldar_, Jun 14 2025
%Y A023839 Cf. A001222, A004344, A023837, A023838, A023840, A023841, A023842, A023843, A023844, A023845, A023846, A023847, A023848, A023849, A023850, A023851.
%K A023839 nonn
%O A023839 2,2
%A A023839 _Clark Kimberling_
%E A023839 Offset corrected to 2 by _Ivan Neretin_, Nov 08 2017