A045759 -id:A045759 - cp's OEIS frontend

A039945 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.

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

Offset: 1

David W. Wilson

Amiram Eldar, Table of n, a(n) for n = 1..10000

Cf. A045759.

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 *)

A045760 Smallest Maris-McGwire k-tuple (k>1) for each k: f(n) = f(n+1) = ... = f(n+k-1), where f is defined in comments.

Original entry on oeis.org

7, 212, 8126, 241995, 3539990, 1330820, 12222533493, 3249880870

Offset: 2

Mike Keith

A045759 generalizes to k consecutive integers that all have the same value of f(n), where f(n) = sum of digits of n plus sum of digits in prime factors of n. The sequence shows the integer which starts the smallest set of k (and no more than k) consecutive integers having this property.

H. Havermann, Maris-McGwire-Sosa 7-tuples, 8-tuples and 9-tuples

Cf. A045759, A006145.

Two more terms from Hans Havermann, Dec 13 2000

Offset changed to 2 by Hans Havermann, Jun 22 2014

cp's OEIS Frontend

A039945 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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