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 A325619 #6 May 13 2019 08:11:38
%S A325619 2,9,375,15625
%N A325619 Heinz numbers of integer partitions whose reciprocal factorial sum is 1.
%C A325619 The Heinz number of an integer partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k).
%C A325619 The reciprocal factorial sum of an integer partition (y_1,...,y_k) is 1/y_1! + ... + 1/y_k!.
%F A325619 Contains prime(n)^(n!) for all n > 0, including 191581231380566414401 for n = 4.
%e A325619 The sequence of terms together with their prime indices begins:
%e A325619 1: {}
%e A325619 2: {1}
%e A325619 9: {2,2}
%e A325619 375: {2,3,3,3}
%e A325619 15625: {3,3,3,3,3,3}
%t A325619 Select[Range[100000],Total[Cases[FactorInteger[#],{p_,k_}:>k/PrimePi[p]!]]==1&]
%Y A325619 Factorial numbers: A000142, A007489, A022559, A064986, A108731, A115944, A284605, A325508, A325616.
%Y A325619 Reciprocal factorial sum: A002966, A051908, A316855, A325618, A325624.
%K A325619 nonn,more
%O A325619 1,1
%A A325619 _Gus Wiseman_, May 13 2019