A339937 - OEIS

%I #9 Dec 24 2020 04:47:48

%S 2282175,33350624,46734975,86424975,87152624,105674624,126114975,

%T 169707824,179762624,214491375,221370975,235857824,266022224,

%U 270586575,278524575,297774224,360021375,372683024,380858624,395715375,425840624,470624175,489873824,503963775

%N Numbers k such that k and k+1 are both coreful abundant numbers (A308053).

%H Amiram Eldar, <a href="/A339937/b339937.txt">Table of n, a(n) for n = 1..1000</a>

%e 2282175 is a term since 2282175 and 2282176 are both coreful abundant numbers.

%t f[p_, e_] := (p^(e + 1) - 1)/(p - 1) - 1; s[1] = 1; s[n_] := Times @@ (f @@@ FactorInteger[n]); abQ[n_] := s[n] > 2*n; q1 = False; seq = {}; Do[q2 = abQ[n]; If[q1 && q2, AppendTo[seq, n - 1]]; q1 = q2, {n, 2, 10^8}]; seq

%Y Subsequence of A308053.

%Y Similar sequences: A096399, A283418, A318167, A327635, A327942, A330872, A331412, A333951.

%K nonn

%O 1,1

%A _Amiram Eldar_, Dec 23 2020