A023822 - OEIS

%I #6 Nov 02 2017 17:51:57

%S 0,3,3,6,5,7,7,10,9,10,9,12,9,12,12,14,13,15,12,19,15,17,17,18,18,20,

%T 19,20,16,21,20,23,20,21,20,23,18,23,21,25,26,27,27,30,27,28,28,31,27,

%U 31,27,33,31,33,31,32,31,33,31,34,30,36,34,34,31,33,31,37,32,35,34,37,36,37,37,39,35,37

%N Sum of exponents in prime-power factorization of C(3n,n-3).

%H Ivan Neretin, <a href="/A023822/b023822.txt">Table of n, a(n) for n = 3..10000</a>

%t Join[{0}, Table[Total[FactorInteger[Binomial[3 n, n - 3]][[All, 2]]], {n, 4, 80}]] (* _Ivan Neretin_, Nov 02 2017 *)

%K nonn

%O 3,2

%A _Clark Kimberling_

%E Offset corrected to 3 by _Ivan Neretin_, Nov 02 2017