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A348276
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Numbers k such that k and k+1 are both noninfinitary abundant numbers (A348274).
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1
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64198575, 84909824, 86424975, 110238975, 113223824, 191206575, 211266224, 224722575, 231058575, 231800624, 240069375, 240584175, 245383424, 262648575, 262911824, 279597824, 293893424, 297774224, 333773055, 338676975, 340250624, 340829775, 347244975, 372683024
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OFFSET
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1,1
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LINKS
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Table of n, a(n) for n=1..24.
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EXAMPLE
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64198575 is a term since A348271(64198575) = 69470136 > 64198575 and A348271(64198576) = 65363424 > 64198576.
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MATHEMATICA
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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
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CROSSREFS
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Cf. A348271.
Subsequence of A096399 and A348274.
Similar sequences: A318167, A327635, A327942, A331412.
Sequence in context: A223288 A223485 A250863 * A164725 A164726 A237157
Adjacent sequences: A348273 A348274 A348275 * A348277 A348278 A348279
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KEYWORD
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nonn
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AUTHOR
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Amiram Eldar, Oct 09 2021
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STATUS
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approved
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