A171183 Numbers n such that sigmawt(n) = sigmawt(n+1), where sigmawt(n) is the sum of the divisors of n weighted by divisor multiplicity in n.

14, 957, 1334, 1634, 2402, 2685, 20145, 33998, 42818, 74918, 79826, 79833, 84134, 111506, 122073, 138237, 147454, 166934, 201597, 274533, 289454, 347738, 383594, 416577, 440013, 544334, 605985, 649154, 655005, 1060802, 1642154, 1674513

Offset: 1

Author

Joseph L. Pe, Dec 05 2009

Keywords

• nonn

Links

• Ray Chandler, Table of n, a(n) for n=1..200

Crossrefs

See A168512 for definition of divisor multiplicity.

Programs

Mathematica

divmult[d_, n_] := Module[{output, i}, If[d == 1, output = 1, If[d == n, output = 1, i = 0; While[Mod[n, d^(i + 1)] == 0, i = i + 1]; output = i]]; output]; dmt[n_] := Module[{divs, l}, divs = Divisors[n]; l = Length[divs]; Sum[divmult[divs[[i]], n]*divs[[i]], {i, 1, l}]]; l = {}; Do[If[dmt[i] == dmt[i + 1], l = Append[l, i]], {i, 1, 10^6}]; l

Extensions

Extended by Ray Chandler, Dec 08 2009