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 A246048 #15 Aug 24 2014 16:56:28 %S A246048 6,12,14,15,21,22,24,26,28,30,35,38,39,42,44,45,46,48,50,51,52,54,55, %T A246048 56,57,58,60,62,63,69,70,74,75,76,77,78,82,84,85,86,87,88,90,91,92,93, %U A246048 94,95,96,98,99 %N A246048 Numbers for which (n^2)! is divisible by n!^n*(2n)!. %C A246048 In general, (n*m)! is divisible by m!^n*n!, cf. A060540 for the quotients. It was asked when it is also divisible by m!^n*(kn)! for some k>1. The present sequence answers this for the special case m=n. For the values m=n=52,69,75,77,78,92,95,... one can take k=3; m=n=120 is the least case where one can take k=4. %C A246048 Farideh Firoozbakht observes that all terms are composite numbers. The comment in A057599 and conjecture in A096126 seem to confirm that there are no primes nor powers of primes in this sequence. %o A246048 (PARI) max_k(n)=for(k=1,m=n,Mod((n*m)!,m!^n*(k*n)!) && return(k-1)) \\ returns the maximal k for m=n. %o A246048 for(n=1,99,a(n)>1&&print1(n,",")) \\ prints this sequence %K A246048 nonn %O A246048 1,1 %A A246048 _M. F. Hasler_, Aug 23 2014