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 A023841 #11 Jun 14 2025 04:18:29
%S A023841 0,2,3,4,5,6,9,9,9,10,11,10,12,13,15,13,15,16,15,15,16,17,21,22,22,22,
%T A023841 24,19,21,22,23,23,23,23,24,25,25,25,28,24,26,31,29,27,29,30,33,33,36,
%U A023841 35,36,36,37,36,39,37,38,37,37,34,36,40,42,38,36,39,40,40,42,42,41,43,43,47,48,45,46,47
%N A023841 Sum of exponents in prime-power factorization of C(5n,n-4).
%H A023841 Ivan Neretin, <a href="/A023841/b023841.txt">Table of n, a(n) for n = 4..10000</a>
%F A023841 From _Amiram Eldar_, Jun 14 2025: (Start)
%F A023841 a(n) = A001222(A004346(n)).
%F A023841 a(n) = A023840(n) - A001222(4*n+4) + A001222(n-3). (End)
%t A023841 Table[PrimeOmega[Binomial[5 n, n - 4]], {n, 4, 81}] (* _Ivan Neretin_, Nov 08 2017 *)
%o A023841 (PARI) a(n) = bigomega(binomial(5*n,n-4)); \\ _Amiram Eldar_, Jun 14 2025
%Y A023841 Cf. A001222, A004346, A023837, A023838, A023839, A023840, A023842, A023843, A023844, A023845, A023846, A023847, A023848, A023849, A023850, A023851.
%K A023841 nonn
%O A023841 4,2
%A A023841 _Clark Kimberling_
%E A023841 Offset corrected to 4 by _Ivan Neretin_, Nov 08 2017