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 A023993 #10 Jun 11 2025 09:14:54 %S A023993 0,3,6,8,8,11,11,14,14,14,17,21,18,20,22,23,21,24,24,27,26,29,29,34, %T A023993 29,30,35,33,32,34,33,39,34,34,37,39,35,38,41,43,40,45,46,50,51,48,49, %U A023993 54,49,50,51,52,49,56,53,55,54,53,58,62,57,58,61,63,56,58,58,61,61,63,62,68,61,65,70 %N A023993 Sum of exponents of primes in multinomial coefficient M(3n; n+2,n-1,n-1). %H A023993 Amiram Eldar, <a href="/A023993/b023993.txt">Table of n, a(n) for n = 1..10000</a> %F A023993 a(n) = A022559(3*n) - A022559(n+2) - 2*A022559(n-1). - _Amiram Eldar_, Jun 11 2025 %t A023993 a[n_] := PrimeOmega[Multinomial[n + 2, n - 1, n - 1]]; Array[a, 100] (* _Amiram Eldar_, Jun 11 2025 *) %o A023993 (PARI) a(n) = bigomega((3*n)! / ((n+2)!*(n-1)!^2)); \\ _Amiram Eldar_, Jun 11 2025 %Y A023993 Cf. A001222, A022559. %Y A023993 Cf. A023978, A023979, A023980, A023981, A023982, A023983, A023984, A023985, A023986, A023987, A023990, A023991, A023992. %K A023993 nonn %O A023993 1,2 %A A023993 _Clark Kimberling_