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%I #5 Oct 12 2021 14:01:27
%S 64198575,84909824,86424975,110238975,113223824,191206575,211266224,
%T 224722575,231058575,231800624,240069375,240584175,245383424,
%U 262648575,262911824,279597824,293893424,297774224,333773055,338676975,340250624,340829775,347244975,372683024
%N Numbers k such that k and k+1 are both noninfinitary abundant numbers (A348274).
%e 64198575 is a term since A348271(64198575) = 69470136 > 64198575 and A348271(64198576) = 65363424 > 64198576.
%t f[p_, e_] := Module[{b = IntegerDigits[e, 2], m}, m = Length[b]; Product[If[b[[j]] > 0, 1 + p^(2^(m - j)), 1], {j, 1, m}]]; isigma[1] = 1; isigma[n_] := Times @@ f @@@ FactorInteger[n]; q[n_] := DivisorSigma[1,n] - isigma[n] > n; seq = {}; q1 = q[1]; Do[q2 = q[n]; If[q1 && q2, AppendTo[seq, n-1]]; q1=q2 ,{n,2,10^8}]; seq
%Y Cf. A348271.
%Y Subsequence of A096399 and A348274.
%Y Similar sequences: A318167, A327635, A327942, A331412.
%K nonn
%O 1,1
%A _Amiram Eldar_, Oct 09 2021