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 A321453 #6 Nov 13 2018 12:54:32 %S A321453 1,2,3,5,6,7,10,11,13,14,15,17,18,19,20,21,22,23,24,26,28,29,31,33,34, %T A321453 35,37,38,39,41,42,43,44,45,46,47,50,51,52,53,54,55,56,57,58,59,60,61, %U A321453 62,65,66,67,68,69,71,72,73,74,75,76,77,78,79,80,82,83,85 %N A321453 Numbers that cannot be factored into two or more factors all having the same sum of prime indices. %C A321453 Also Heinz numbers of integer partitions that cannot be partitioned into two or more blocks with equal sums. The Heinz number of an integer partition (y_1, ..., y_k) is prime(y_1) * ... * prime(y_k). %C A321453 A prime index of n is a number m such that prime(m) divides n. The multiset of prime indices of n is row n of A112798. The sum of prime indices of n is A056239(n). %e A321453 The sequence of all integer partitions that cannot be partitioned into two or more blocks with equal sums begins: (1), (2), (3), (21), (4), (31), (5), (6), (41), (32), (7), (221), (8), (311), (42), (51), (9), (2111), (61), (411). %t A321453 hwt[n_]:=Total[Cases[FactorInteger[n],{p_,k_}:>PrimePi[p]*k]]; %t A321453 facs[n_]:=If[n<=1,{{}},Join@@Table[Map[Prepend[#,d]&,Select[facs[n/d],Min@@#>=d&]],{d,Rest[Divisors[n]]}]]; %t A321453 Select[Range[100],Select[facs[#],And[Length[#]>1,SameQ@@hwt/@#]&]=={}&] %Y A321453 Positions of 1's in A321455. %Y A321453 Cf. A056239, A112798, A276024, A279787, A305551, A306017, A317144, A320322, A321451, A321452, A321454. %K A321453 nonn %O A321453 1,2 %A A321453 _Gus Wiseman_, Nov 10 2018