%I #12 Feb 14 2021 15:19:45
%S 1,6,30,145,151,592,732,3895,87806,292432
%N Numbers k such that Sum_{j=1..k1} (4j)!/5^j is an integer.
%C Next term is > 1500000.
%t seq={}; sum=0; fak=1; k=0; While[k<10000, sum+=fak; If[Denominator[sum]==1, AppendTo[seq,k+1]]; k++; fak*=4*k*(4*k1)*(4*k2)*(4*k3)/5;]; seq
%Y Cf. A215972, A216042, A216043, A216044.
%K nonn,more
%O 1,2
%A _Vaclav Kotesovec_, Aug 30 2012
