OFFSET
1,2
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..8193
MATHEMATICA
f[n_] := If[Length@ # == 1 && #[[1, 1]] == 1, {0}, Sort@ #[[All, -1]]] &@ FactorInteger@ n; Table[k = 1; While[f@ k != #, k++] &@ f[2 n - DigitCount[2 n, 2, 1]]; k, {n, 106}] (* or, faster *)
Table[Times @@ MapIndexed[(Prime@ First@ #2)^#1 &, #] &@ If[Length# == 1 && #[[1, 1]] == 1, {0}, Reverse@ Sort@ #[[All, -1]]] &@ FactorInteger[2 n - DigitCount[2 n, 2, 1]], {n, 106}] (* Michael De Vlieger, Nov 21 2016 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Nov 19 2016
STATUS
approved