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 A023845 #15 Jun 14 2025 04:18:57
%S A023845 1,5,4,8,7,8,9,12,9,12,13,14,14,16,13,18,15,17,16,22,17,18,20,21,19,
%T A023845 24,23,26,24,24,24,27,23,25,25,28,24,29,28,32,29,30,28,33,31,31,31,32,
%U A023845 32,36,33,39,36,38,38,42,35,43,42,45,41,39,38,41,40,40,38,44,41,42,45,47,43,47,44,48,48
%N A023845 Sum of exponents in prime-power factorization of binomial(5n, n+3).
%H A023845 Ivan Neretin, <a href="/A023845/b023845.txt">Table of n, a(n) for n = 1..10000</a>
%F A023845 a(n) = A023844(n) + A001222(4*n-2) - A001222(n+3). - _Amiram Eldar_, Jun 14 2025
%t A023845 Table[Total[Transpose[FactorInteger[Binomial[5n,n+3]]][[2]]],{n,80}] (* _Harvey P. Dale_, Aug 12 2012 *)
%t A023845 a[n_] := PrimeOmega[Binomial[5*n, n+3]]; Array[a, 100] (* _Amiram Eldar_, Jun 14 2025 *)
%o A023845 (PARI) a(n) = bigomega(binomial(5*n,n+3)); \\ _Amiram Eldar_, Jun 14 2025
%Y A023845 Cf. A001222, A023837, A023839, A023840, A023841, A023842, A023843, A023844, A023846, A023847, A023848, A023849, A023850, A023851.
%K A023845 nonn
%O A023845 1,2
%A A023845 _Clark Kimberling_