cp's OEIS Frontend

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.

A301987 Heinz numbers of integer partitions whose product is equal to their sum.

This page as a plain text file.
%I A301987 #10 Mar 27 2019 12:33:18
%S A301987 2,3,5,7,9,11,13,17,19,23,29,30,31,37,41,43,47,53,59,61,67,71,73,79,
%T A301987 83,84,89,97,101,103,107,108,109,113,127,131,137,139,149,151,157,163,
%U A301987 167,173,179,181,191,193,197,199,200,211,223,227,229,233,239,241,251
%N A301987 Heinz numbers of integer partitions whose product is equal to their sum.
%C A301987 The Heinz number of an integer partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k).
%H A301987 Alois P. Heinz, <a href="/A301987/b301987.txt">Table of n, a(n) for n = 1..10000</a>
%e A301987 Sequence of reversed integer partitions begins: (1), (2), (3), (4), (2 2), (5), (6), (7), (8), (9), (10), (1 2 3), (11), (12), (13), (14), (15), (16), (17), (18), (19), (20), (21), (22), (23), (1 1 2 4), (24), (25), (26), (27), (28), (1 1 2 2 2), (29), (30).
%p A301987 q:= n-> (l-> mul(i, i=l)=add(i, i=l))(map(i->
%p A301987     numtheory[pi](i[1])$i[2], ifactors(n)[2])):
%p A301987 select(q, [$1..300])[];  # _Alois P. Heinz_, Mar 27 2019
%t A301987 primeMS[n_]:=If[n===1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]];
%t A301987 Select[Range[300],Total[primeMS[#]]===Times@@primeMS[#]&]
%Y A301987 Cf. A001055, A002865, A003963, A056239, A276024, A284640, A296150, A299701, A301957, A301988.
%K A301987 nonn
%O A301987 1,1
%A A301987 _Gus Wiseman_, Mar 30 2018