cp's OEIS Frontend

A336426 Numbers that cannot be written as a product of superprimorials {2, 12, 360, 75600, ...}.

%I A336426 #7 Jul 27 2020 00:24:33
%S A336426 3,5,6,7,9,10,11,13,14,15,17,18,19,20,21,22,23,25,26,27,28,29,30,31,
%T A336426 33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,49,50,51,52,53,54,55,56,
%U A336426 57,58,59,60,61,62,63,65,66,67,68,69,70,71,72,73,74,75,76
%N A336426 Numbers that cannot be written as a product of superprimorials {2, 12, 360, 75600, ...}.
%C A336426 The n-th superprimorial is A006939(n) = Product_{i = 1..n} prime(i)^(n - i + 1).
%e A336426 We have 288 = 2*12*12 so 288 is not in the sequence.
%t A336426 chern[n_]:=Product[Prime[i]^(n-i+1),{i,n}];
%t A336426 facsusing[s_,n_]:=If[n<=1,{{}},Join@@Table[(Prepend[#,d]&)/@Select[facsusing[Select[s,Divisible[n/d,#]&],n/d],Min@@#>=d&],{d,Select[s,Divisible[n,#]&]}]];
%t A336426 Select[Range[100],facsusing[Array[chern,30],#]=={}&]
%Y A336426 A181818 is the complement.
%Y A336426 A336497 is the version for superfactorials.
%Y A336426 A001055 counts factorizations.
%Y A336426 A006939 lists superprimorials or Chernoff numbers.
%Y A336426 A022915 counts permutations of prime indices of superprimorials.
%Y A336426 A317829 counts factorizations of superprimorials.
%Y A336426 A336417 counts perfect-power divisors of superprimorials.
%Y A336426 Cf. A000325, A005117, A076954, A124010, A294068, A336419, A336420, A336421, A336496, A336500, A336568.
%K A336426 nonn
%O A336426 1,1
%A A336426 _Gus Wiseman_, Jul 26 2020