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A039945
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Maris-McGwire numbers(2): numbers k such that f(k) = f(k+1), where f(k) = sum of digits of k + sum of digits of the distinct prime factors of k.
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3
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3, 12, 14, 45, 61, 118, 122, 124, 137, 143, 152, 213, 224, 225, 242, 273, 277, 356, 373, 390, 392, 398, 421, 428, 455, 457, 460, 462, 464, 510, 526, 537, 560, 590, 607, 621, 673, 680, 692, 746, 782, 797, 804, 818, 820, 866, 878, 922, 939, 944, 965, 980, 985
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OFFSET
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1,1
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LINKS
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Amiram Eldar, Table of n, a(n) for n = 1..10000
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MATHEMATICA
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ds[n_] := Plus @@ IntegerDigits[n]; f[n_] := ds[n] + Total[ds /@ FactorInteger[n][[;; , 1]]]; s = {}; f1 = 1; Do[f2 = f[n]; If[f1 == f2, AppendTo[s, n-1]]; f1 = f2, {n, 2, 1000}]; s (* Amiram Eldar, Nov 24 2019 *)
SequencePosition[Flatten[Table[Total[IntegerDigits[n]]+Total[Flatten[IntegerDigits/@FactorInteger[n][[All, 1]]]], {n, 1000}]], {x_, x_}][[All, 1]](* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jan 09 2021 *)
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CROSSREFS
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Cf. A045759.
Sequence in context: A242130 A286386 A032918 * A227302 A201273 A221920
Adjacent sequences: A039942 A039943 A039944 * A039946 A039947 A039948
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KEYWORD
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nonn,base
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AUTHOR
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David W. Wilson
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STATUS
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approved
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