The OEIS is supported by the many generous donors to the OEIS Foundation.
%I #19 Nov 10 2025 12:05:09
%S 10392284335,11971434307,39817292107,64231546567,72396994231
%N Composite non-semiprime solutions m to m'' = m'-1, where m' and m'' are the first and the second arithmetic derivatives of m.
%C Equivalently, non-semiprime solutions for m' = q, where q is a primary pseudoperfect number (A054377). Terms a(1)-a(5) correspond to A054377(6). Term a(6) would be a solution to m' = A054377(k) with k >= 8.
%C All composite solutions are listed in A189803, unrestricted solutions are listed in A189710.
%e a(1) = 10392284335 = 5 * 83 * 997 * 25117 is a solution to m' = A054377(6) = 2214502422.
%Y Subsequence of A189710 and A189803.
%Y Cf. A003415, A054377, A390533.
%K nonn,more,hard
%O 1,1
%A _Max Alekseyev_, Nov 09 2025