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 A023837 #19 Jun 14 2025 04:18:15
%S A023837 0,1,3,3,4,6,7,8,8,7,9,12,11,14,13,14,12,15,14,15,18,17,17,19,18,17,
%T A023837 23,22,21,25,23,26,21,23,22,24,23,24,27,27,27,27,29,27,28,31,30,33,28,
%U A023837 31,32,33,36,38,36,38,37,35,39,40,41,41,41,39,34,38,38,38,39,41,39,46,41,43,45,43,45,48,47
%N A023837 Sum of exponents in prime-power factorization of C(5n,n).
%H A023837 Ivan Neretin, <a href="/A023837/b023837.txt">Table of n, a(n) for n = 0..10000</a>
%F A023837 a(n) = A001222(A001449(n)). - _Amiram Eldar_, Jun 14 2025
%p A023837 with(numtheory):a:=proc(n) if n=0 then 0 else bigomega(binomial(5*n,n)) fi end: seq(a(n), n=0..78); # _Zerinvary Lajos_, Apr 11 2008
%t A023837 Table[PrimeOmega[Binomial[5 n, n]], {n, 0, 78}] (* _Ivan Neretin_, Nov 08 2017 *)
%o A023837 (PARI) a(n) = bigomega(binomial(5*n,n)); \\ _Amiram Eldar_, Jun 14 2025
%Y A023837 Cf. A001222, A001449, A023838, A023839, A023840, A023841, A023842, A023843, A023844, A023845, A023846, A023847, A023848, A023849, A023850, A023851.
%K A023837 nonn
%O A023837 0,3
%A A023837 _Clark Kimberling_
%E A023837 Offset changed to 0 and a(0) prepended by _Amiram Eldar_, Jun 14 2025