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 A081259 #11 Jul 18 2015 08:40:27 %S A081259 2,5,7,11,13,17,19,23,23,29,31,31,37,41,43,47,47,53,53,59,61,61,67,71, %T A081259 73,73,79,83,83,89,89,89,97,101,103,107,109,113,113,113,113,113,127, %U A081259 131,131,137,139,139,139,149,151,151,157,157,163,167,167,173,173,179,181 %N A081259 a(n) is the smallest k such that C(3n,n) divides k!. %C A081259 a(n) is the largest prime < 3n. More generally the smallest k such that C(mn,n) divides k! is the largest prime < mn. %F A081259 a(n) = A151799(3n). - _R. J. Mathar_, Jul 18 2015 %t A081259 NextPrime[3Range[70],-1] (* _Harvey P. Dale_, Oct 20 2011 *) %o A081259 (PARI) a(n)=if(n<0,0,s=1; while(k!%binomial(3*n,n)>0,k++); k) %Y A081259 Cf. A060308, A151799. %K A081259 nonn %O A081259 1,1 %A A081259 _Benoit Cloitre_, Apr 20 2003