cp's OEIS Frontend

A336942 Number of strict chains of divisors in A130091 (numbers with distinct prime multiplicities) starting with the superprimorial A006939(n) and ending with 1.

%I A336942 #13 Sep 02 2020 23:06:17
%S A336942 1,1,5,95,8823,4952323,20285515801,714092378624317
%N A336942 Number of strict chains of divisors in A130091 (numbers with distinct prime multiplicities) starting with the superprimorial A006939(n) and ending with 1.
%F A336942 a(n) = A336423(A006939(n)) = A336571(A006939(n)).
%e A336942 The a(0) = 1 through a(2) = 5 chains:
%e A336942   {1}  {2,1}  {12,1}
%e A336942               {12,2,1}
%e A336942               {12,3,1}
%e A336942               {12,4,1}
%e A336942               {12,4,2,1}
%t A336942 chern[n_]:=Product[Prime[i]^(n-i+1),{i,n}];
%t A336942 chnstr[n_]:=If[n==1,1,Sum[chnstr[d],{d,Select[Most[Divisors[n]],UnsameQ@@Last/@FactorInteger[#]&]}]];
%t A336942 Table[chnstr[chern[n]],{n,0,3}]
%Y A336942 A076954 can be used instead of A006939 (cf. A307895, A325337).
%Y A336942 A336423 and A336571 are not restricted to A006939.
%Y A336942 A336941 is the version not restricted by A130091.
%Y A336942 A337075 is the version for factorials.
%Y A336942 A074206 counts chains of divisors from n to 1.
%Y A336942 A130091 lists numbers with distinct prime multiplicities.
%Y A336942 A181796 counts divisors with distinct prime multiplicities.
%Y A336942 A253249 counts chains of divisors.
%Y A336942 A327498 gives the maximum divisor with distinct prime multiplicities.
%Y A336942 A336422 counts divisible pairs of divisors, both in A130091.
%Y A336942 A336424 counts factorizations using A130091.
%Y A336942 Cf. A000005, A001055, A002033, A032741, A067824, A124010, A167865, A336419, A336420, A336500, A336568.
%K A336942 nonn,more
%O A336942 0,3
%A A336942 _Gus Wiseman_, Aug 14 2020